The only issue with wall/ceiling speakers is that you greatly limit the arrangement of the room. If you plan to build a theater that doesn't ever change shape (furniture, equipment, etc), then they are a great way to keep speakers off the floor and more or less out of sight. Many times they can sound very good...depends on the installation, the source of the signal, and the quality of the components. You may want to play with different arrangements before running wire and/or setting speakers. Good luck!
He seems to be happy with how they work. They do however transmit through both sides of the wall. He has them in the ceiling in basement theater system and the sound comes through the floor upstairs. Could be good for filling the house, if you're having a party, but not so good if you're watching the latest action thriller and the kids are supposed to be asleep in the next room.