Depends on what you want to do, the internet is battling about it every day.
The tire size of 29" lets you run over obstacles much easier, while the 26" will let you have a nimbler and faster bike.
I assume you've tried out 26" before so ask your LBS about loaning a 29" bike to try out in your local trails, it does feel different.
However I'm all for 26" seeing as standoverheight is an issue for me with the 29"er bikes. (Larger tires, taller standoverheight) If you look into '650b' it's kind of in the middle of 26" and 29".
So my conclusion is that there is no better, they both do different jobs well so it all boils down to how you ride and personal preference.