Typically, it's not a great idea. 29'ers are designed with very specific geometry to handle the 3" larger wheels. I'm guessing the guy who said it handled great might not really know what a great handling bike is. Ride your 26" bike, then if you could ride a Niner Air9, Specialized Camber, Marin NailTrial, Giant XtC, etc.
If your terrain is conducive to a 29er, a dedicated 29" bike will work wonders - roll over rocks and roots better, climb really well with those larger contact patches, descend confidently, etc.
I think you're full of s*it. There isn't one shred of scientific proof that 29" MTB wheels outperform 26" wheels. Sure, they perform differently, but whether that difference is better or worse is up the the rider and their preferences and riding style.