In reply to paul fleuriot:
Moved from a lifetime of riding 26" to 29" about 2 years ago. Initially bought a Trek hardtail as I didn't know if I would like the size change, then to a Giant full sus a few months ago. Almost everything is better with bigger wheels, and it's faster and easier to handle over pretty much all terrain.
I wouldn't say that an extra 3" of wheel is the equivalent of 4" of rear suspension travel, however a 29" hardtail will deal with much more than a 26" hardtail.
If you want to be really picky then it is slightly more awkward on very narrow, twisty, rocky, uphill technical sections. But to be honest this is the type of stuff you would be better off getting off and walking.
Cezza