I know it's a bit of a gravedig, but came across this thread while on a search from another and thought I'd post my thoughts.
After many years of 26ers (back from the mid-90s), I was a bit of an early adopter with 29ers and bought the first Specialized Stumpy 29er (hardtail) one day when all I needed was a new tube for my road bike - this was mid-2008. I just really liked the visual proportions of the 29er wheels on a large frame. I've always thought 26" wheels look just a little too small on anything bigger than a medium.
This started a run of 29ers for me over the next few years where I just couldn't seem to land on one that steered like I wanted it to. I genuinely believed they made me faster on pretty much everything except really tight stuff, but I was definitely slower on super-techie singletrack. The fact that bigger wheels necessitated wider bars was also a problem on any trails where you're constantly squeezing through narrow gaps in trees.
So essentially, I stopped having fun on my favourite trails. I was racing faster in 100km races with lots of open fire trail, but my social riding was suffering at the same time and jumping? Well, I was never that good in the air, but I really sucked at it on big wheels. When you add all that up, I was basically becoming a roadie; the sort of rider I'd despised for more than a decade. Fit and fast in a straight line, but f*(&ing useless on loose corners or jumps.
So, fast forward a few years and I'm looking at a garage with 3 so-so mountain bikes of varying wheel sizes and realising that I don't love any of them and I'm even having trouble deciding which bike to ride on any given day for any trail. It was all getting very demotivational. So the penny dropped, I cracked the shits and put everything MTB-related up for sale. Sold literally everything I'd collected over the years and started from scratch on the search for the perfect 26" "one bike".
Enter the Trek Fuel EX9. Not the best at anything, but pretty bloody good at everything except DH. Looks the goods (even for a 26er) and has all the new mod cons - tapered headtube, 15/142 through axles, floating rear shock, DRCV front and rear, internal stealth routing for the dropper. All the good gear.
It's now been to Rotorua, where it ticked every single trail in the Redwoods except the DH course. I briefly rode a couple of other bikes while I was there, including a new Giant Trance 27.5 and the only thing that told me was how quickly I wanted to get back on my Fuel. I saw some pretty bling bikes while I was over there, but was never ashamed to be out on the Fuel.
And now the Fuel has taken me to the top of B grade and a promotion to A grade at the local dirt crits. Sure, I bought a lighter wheelset for XC racing, but @ $700, it was a lot cheaper than buying a whole new race bike and has given the Fuel some real pep in its step. At the end of the day, I'm a 39 year old workaholic dad who smoked for most of the last 25 years and doesn't have time for any structured training - the fact I'm racing reasonably quickly has a LOT to do with a bike that has mistake-proof handling and simply motivates me to ride my guts out every time I'm on it.
The irony of chucking in 29ers (probably for good now that 27.5 is on the rise) and buying the Fuel was that it was only a few months later that Trek changed the Fuel to a 29er. Do I wish I'd waited those few months and gone with the bigger wheels?
No way. 26 ain't dead for riders like me who aren't overly tall (I'm 185cm / 6'1") and need a single bike to do everything. Absolutely loving it. There's never a single second where I'm thinking "geez, I wish I had x% less rolling resistance over that trail irregularity" (in my opinion this whole "angle of attack" argument is null and void on a dual-suspension bike, but anyway...), but there are moments every time I ride where I wonder how I put up with stupid big wheels for almost 5 years.
Footnote: Imagine my joy when I recently raced a 3 hour enduro in a location generally regarded as "29er heaven" and saw the elite men's winner on.. wait for it... 26".