26" are more fun, more sporty and more aggressive. Available parts, better parts

29" are more safe - the wheel size helps with cracks, harder to push and may hang you up in technical spots. Heavier, worse hill climb ever.

Really, when I build bikes for the shops around town, I do test them out. When I test them, I find a smile on my face with the 26" and not the 29". I'm a very technical rider, so the best way I can maneuver is the best choice.

IMHO