I've tried it. It's good for indoors in that it doesn't use baro-assisted altitude control (which can be disrupted by pressure changes in a building) or GPS (which doesn't work at all), but the throttle in Stabilize mode (the mod that doesn't use baro and GPS) is a bit twitchy. So I suggest practicing outside with it to get a feel for how it flies. You don't really want to experience Stablize's throttle response for the first time when there's a ceiling in the way. It can climb really fast in that mode.