I have just got myself a 29 inch wheeled thing for xc racing.
Its not actually that light at the moment, at 24lbs its a fair chunk heavier than my Ti Hardtail that it has replaced, but I will soon be completing the XTR group set so will make it a fair bit lighter.
Despite the present extra weight, I'm faster on the new bike, although it also has disc brakes and the latest Rockshox SID ultimate which I have to say, are incredible.
The rims in general are a lot wider, so tyres can be ran at lower pressure and still be well supported. I have burped the 26 tyres on a few occasions.
I have a lot more confidence in the new bike, I absolutely love it. It has saved my ass a few times already, and I only used it at Mayhem (built that week) and then one evening race.
I switch bikes often, I tend to commute on a road or gravel bike, but sometimes 26ers come out. Still fun to ride, but I choose where I ride them, rather than following a course between the tapes.
It takes a bit of getting used too as my first impression when going back to 26 is it feels like being on a little kids bike, I also feel a lot more top heavy and front heavy.
To summarise, if you want to feel everything going on underneath you and make it feel like your working hard, go 26.
If you want to feel everything going on underneath you and make it feel like your working hard, but go a bit quicker and yet also have a just a bit more margin to help you stay on the bike and out of trouble, go 29
FYI, I have a Specialized Chisel frame, it is an awesome bit of kit and I have built it with a nod to the 90's theme.