In-wall speakers can be alright, but you had better make sure you figure out exactly which ones you want before you actually try them in place, and you need to figure out exactly where you want them before installation. With ordinary speakers, if you don't like the sound, repositioning the speakers is generally relatively easy, but changing your room layout with in-wall speakers involves putting new holes in your walls and patching up the old ones, not to mention the bother of rerouting the wires.
In most cases, I think people would be better off with regular speakers, but the in-walls have the advantage of being out of the way.