I was trying out a 29er for the first time on the Borrowdale bash (Lakes) last week and I was very Impressed with the Orange Gyro and Five 29er.
The ride was so much faster than a 26er and the section down Birkett Leap (Watendlath to Rosthwaite was noticeably easier and overall the bikes were great fun to ride.
Would i buy one? No, I really can’t get on with the look of bigger wheels, and although after riding and appreciating the benefits I do prefer the more involved ride 26in bikes give you.
I really hope manufacturers adopt the 650b 27.5 standard as the bikes still look good and in theory will ride/roll a bit better than a 26in wheel.