Inceiling speakers
In my experience, you get much less performance for the money on in-ceiling type speakers. For example, a high end speakercraft speaker might have comparable performance to a less expensive bookshelf speaker wall mounted and pointed at the listening position. Also keep in mind that the Dolby sound track is mixed for surround channels that are on the sides of the listening position, not above you head.
Inexpensive inceling speakers, however, are great for the background music in a whole house system.
If you are considering Axiom, their QS8's mount flush with the wall and would make a great surround speaker paired with bookshelf, floorstander, or their in-wall speakers up front.