It seems nearly every speaker company has jumped to meet consumer interest. The idea gets the wife approval factor (WAF.)
Unfortunately, to hide as in-wall, in-ceiling, or nearly as convenient as thin & on-wall, has to fight some laws of physics.
Assuming that this is for more than background music but stopping shy of higher end, near audiophile stuff, leaves the great, fuzzy middle.
Sources say in-wall sound can be very different from one source to another, emphasizing the necessity to listen critically to whatever demonstrations you can find.
What limited feedback I've heard tends to give Polk high marks for getting into this field early and seriously. Boston Acoustics were also recommended highly. Energy brand is in there, too.
I've heard of implementation by others as seriously compromised, again indicating listening to the group available to consider as essential to avoid a pig in a poke disappointment.
in wall fronts and center, in-celing rears. need a sub as well. looking for great quality but not necessarily audiophile, top-of-the-line stuff.