29 inch wheels are supposed to roll smoother over bumps, as they have a larger circumference. The disadvantage is inertia & more effort is required to get them rolling, and fewer tyres for them, although more are coming onstream regularly. Many XC racers use 29ers at specific times, when courses suit them. It's still a contentious issue, and one which can polarise a MTB conversation.
I'd say, like any bike, try it & see if you like it. Personally i have no issues with my XC racer on 26" wheels.
29ers require longer chainstays & forks, but dont need a larger frame height, so shortarses too can ride them