Summary: I'm a big Polk fan. In fact most of my upcoming house build will feature Polk products (in-wall, in-ceiling speakers, and in-floor and in-wall subs). I am installing 4 for these in-floor subs in my great room powered by 2 Polk SWA500's (designed to match up w/these subs).
Pros: performance, out of sight sub
Cons: under 30 hz material, pricey when you consider the cost of the sub and amp compared to a "normal" sub, but then again it would take up floor space.
Summary: It's not perfect, but it's darn good. I bought 2 for my living room, which is 12x18, and it rocks pretty hard. I built a "false" wall to house these, a left and right in-wall speaker and a center channel, as well as to hide the wires to my TV which is wall mounted.
Summary: The product by itself is a great design but for it to be installed properly you need a big area in your ceiling to mount this baby. If you have a walk around ceiling--like Maryland homes do-- there would be no problem to mount this product. Buyer beware of size problems..
Summary: This is the sub for my living room where I have 5.1 in the walls. I watch movies and TV and also listen to a lot of music in the room. This sub is mounted in the wall of the A/V closet, with the grill facing out into the room.