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.