Revels are good, Episodes are nearly as good for 1/4 the price. Nobody knows about them but they are definitely better than WalMart level of sound.

No ceiling speaker is ever going to sound great. There's too much working against it. As long as you have good fronts in the M80s, don't fret too much about surrounds. They don't have to do all that much and if you're hiding them in the ceiling anyway they'll never meet their full potential. Just find the best value and be done with it.

IMHO, the best value in ceiling speakers is Episode.