So here is the review mash up for the 2nd year, looking at bike, bags and tires. I am not a good reviewer, I can't explore all the features well but will point out what went wrong. I generally have no beef with any pieces of my kit except for tires.

note: I received the blackburn, niner and wtb gear for free but I've done my best to give an objective review

Bikes

This year I got a chance to ride a full suspension 29er (Niner - jet9) and my old Surly Troll. Both with bikepacking setup. Here is what I think about them.

Weight - the Niner is aluminum, making it much lighter even with the full suspension. Riding the Troll after a summer with the light bike was a big change, I can definitely feel it when pushing or carrying the bike uphill.

Aluminum vs steel - steel being easier to repair is definitely a bonus. It is less likely to leave you stranded in the middle of nowhere but there are some high end touring bikes with aluminum frames. I think if I ever need to replace my frame, I will try to get alum.

26 vs 29 - books can be written on this but I will just say what I think from traveling perspective. 29 rolls much better (ruts, rocks, etc.). When it comes to wheel, tire and tube availability, you can run into trouble. That being said, you can fit 26" wheels on a 29" frame, stretch tubes and wheels if done right are not likely to give you trouble. I know of one other person riding a 29er from Alaska but I prefer being able to put on cheap replacement parts when in a pinch. But the downside is they just don't sell $3 downhill monkeys for 29ers.

Suspension (air front & rear on Niner vs coil front on Troll) - There are times I wished I had rear suspension on the Troll, I really like the coil front fork - maintenance free but a little heavy and once loaded you don't get a whole lot of travel. For the dual suspension on the 29er, it was great but having to replace seals and so on will prove very expensive over time. Too many moving parts for the rear and too many things that can go wrong, ohh and that creaking sound, driving me crazy!

Wheels (SRAM Roam 50 vs custom Deore/Rhynolites)
Its kind of an unfair comparison but here it is.

I really can't begin to tell you what I've put Chris Murray's wheels through.

Breaking spokes - both wheels had spoke breakages, all due to rocks or falls. Roam had 1 and Rhynolites 3. The straight pull spokes can be replaced on the spot but I had difficulty finding them at bikeshops on the GDMBR.

(note Chris built my wheels back in 2014 and there was a lot of use and abuse and also a heavy touring load for 1 year.)
The Roam 50's rim was beginning to crack by the end of the GDMBR. This could have been a big problem later.

Hubs: SRAM - no problems here, the hubs worked perfectly.
Deore XT (the old steel ones) - best bang for the buck and surprisingly tough. 2 years on the rear and still working perfectly. I will likely be replacing the engagement points (freehub) as that has been funky lately and I expect it to break soon.
Supernova Infinity S (front dynamo hub) - worked good until I stored my bike over the summer then I discovered the hub has seized. It would have cost over 80$ to get it serviced (which may or may not fix the problem) and not to mention rebuilding the wheel. I ditched it and got another wheel.

"dude... when was the last time you cleaned your chain?"

Drivetrains, random 9 speed vs SRAM XX1. While bikepacking and bicycle touring I don't think one can fully appreciate the responsiveness of the XX1 train, thus to me it is the same wether it shifts smoothly or I have to give the deraileur a little kick. A 28T front ring will give you perfect granny gear on XX1 and the entire drivetrain lasts a lot longer. The problem is a new cassette was $350 (X01 is a little cheaper).

conclusion drivetrains: for traveling, I found getting "brand" components for 9 speed was also not cheap and there is quite a bit of extra cost in Central America but so was the 11speed. In the end, 9 speed is cheaper and easier if you are in a pinch but if you want decent parts - you will still need to go to a larger city/bike shop and get it.

oh yeah! Brakes! because sometimes you have to stop.
SRAM Guide vs BB7. Hydraulic definitely feel more responsive and if I am changing breaks that's what I'll go with. Drawback is if something goes wrong in the middle of nowhere - you may not be able to fix it. I've had terrible experience with wear - a friend rode the entire GDMBR from Banff and to Guatemala on... a single set of brakepads.... I changed the pads at least 7 times.
BIG PROBLEMS with stuff off the BB7's melting and not turning.

conclusion: I would take a 29er over 26 in a heartbeat, keep it to front suspension only and make sure the wheels are built for touring (and not general MTB use). However, as my travels are often on the low budget side, I don't think the advantages outweigh the expensive parts and possibility of getting stuck with a repair you can't afford.

Saddles

Brooks Cambium C17 - had this one for a while now, it's comfortable and maintenance free. If I have a streak of 5-6 long days of riding my bum starts hurting but that has rarely been the case, as there are many pushbike climbs and many days when I arrive at the perfect camping spot a little too early. The creaking can get very annoying but it's manageable.
WTB Rocket - I have tried 3 different rockets (one of them was SPEED, I think), one on my old road bike which I absolutely loved and one in 2014 which was very very bad (the wear 2 pairs of bike shorts and sit sideways for 8 hours kind of bad). In summer I rode with the model which has Gel and it worked pretty good. Better on dirt roads and trails than the C17 and no issues while riding 100+ mile days on the GDMBR, although that gel one was ripping apart after just 3 months.

conclusion: I can't really recomend one over the other. I am happy with the C17 which is on my bike but with the amount of rough roads I would rather have a proper MTB saddle, if I could ever find the WTB Rocket I had on my old bike I would use that.

Bags and stuff

The Outpost Handlebar Roll comes with a nice, durable dry bag which opens on both sides, two straps which allow you to have another dry bag on top if needed. Very happy with the setup and never had major issues. The removable dry bag is very handy if a horseman offers to carry your stuff up a hill!
issues: The bolts attaching the bag holder to the mounting part can get undone if riding very rough terrain (easy fix by inserting longer bolts and 2x nuts on other side to lock them).
note: I have the model which has small metal wire around the stem and push button to release. The 2016 ones I tried for a little had ziptie-like loop around the stem and twist button to release the holder. Not found of either of these features as the ziptie would slide off during heavy bumps and falls, and the twist button constantly gets stuck.
conclusion: despite few issues I am happy with the bags. I kept my old wire/push release version over the new ziptie/twist release.

my "Ray Boys" ding about as good as the bag they are in!

The Outpost Seat Pack. Removable, durable bag, you can strap extra stuff on top or on the side. The straps broke after 5 months but the extra locking thingy makes them usable even after that.
conclusion: super happy with it, recommended.

The Outpost Top Tube Bag. The zipper compartment is good for storing small screws, brakepads, etc. Nothing special about it, the zippers give out after few months (considering I keep my camera there and take it out 20-50 times a day)
conclusion: if you are going to keep your camera there - look for magnet/velcro close or straight up zipper.

+1 on removable bags - you never know who might offer to lighten the load!

The Outpost Frame Bag vs Cleaveland Mountaineering Custom Bags. Cleaveland's bag was amazing - he made it out of a cardboard trace to fit the 29er frame perfectly, durable zippers and walls but I managed to break a zipper anyway. The Blackburn bag is quite a bit smaller than my frame but that leaves just enough space for a bottle holder with stove fuel. Walls are thin, zippers are tiny but it has done well, only problem is if you pack too many things in it, it bulges out a bit. Both bags get water in during a downpour and I think that's normal if you have zippers.
conclusion: Happy with both, Cleaveland made it much tougher but I am yet to find major problems with the Blackburn bag (note: both bags get so stuffed with stuff that I never fully close them unless raining).

Blackburn Cargo Cages - yup! love them. some ductape and hoseclamps do the job on suspension forks.

Bring a drybag, melons, coconuts or your baby brother along!

Tires

Sadly life is not like a Rick Astley song and tires have let me down multiple times. Here is my experience with tires over 2 years, in hopes of finding the perfect tire I got to try and destroy quite a few on the way... and still looking.

Schwalbe Marathon Mondial - No problems while touring paved roads and a little bit of dirt, a good 4000 kilometers on the rear tire. On the backroads of Mexico, the sidewalls were toast in under 1000km, very disappointing and tough to find new tires in the middle of nowhere.

Kenda Nevegal -Got them for the GDMBR in winter, they lasted surprisingly long - until Colorado with some tire swapping, although having all the snow on the roads was definitely easier on them. Another Kenda (don't remember the exact model but had the name 'nevegal' in it as well) didn't do so well and got a sidewall gash before wearing out.

WTB Nano - sidewall troubles. I ran them a little below 30psi, 1 major blowout and 2 that were impending.

Maxxis Adrent & some downhill one on the back - it felt that they wore out too quick but in the end lasted quite a while. Strong sidewalls but also I didn't do as many rough roads during the time I had them.

Surly ET - this was supposed to be the solution to everything, 2.5 and 'designed for off road'. The tire wore out in 2 weeks and I had to put it on the front, which was now like having a beach cruiser bubble tire on the front while going on downhill courses, not fun.

while cheap tires in latin america can be good, be ware with inner tubes!!! only good for fold up baloons for kids

Random finds in Central American supermarkets - at $3-5 a pop, these are hard to beat, assuming you can get one wide enough to fit on your rims. (this is big. some of them you can barely fit and will have to cut them to remove them)
They are heavy and made from hard compound (good wear) but it just feels that if they fail, they will fail catastrophically. Right now I have 2 of them and will report in 2017 on how they do.

conclusion: I had a brief but good experience with a schwalbe Nobby Nick and it seemed to work great. Kenda Nevegals are good (make sure you get the hard component) and so are the cheap supermarket tires if you can find them.

so yeah thats about it.