I currently have a single psw505 in my living room (18X15) that is open to the 12X11 dining room, 9X10 breakfast room, kitchen, stairs and upstairs. The living room ceiling height is basically the roofline (2 story house). For the price and my room size, i dont think anything can touch it. I couldnt be happier with my $200 purchase...key point is $200.
The psw505 is not something i would use for a dedicated theater, but for the price it makes a nice addition to an everyday TV watching/music listening set-up, and movie watching if you don't need to feel every sub-25Hz note at reference levels. Im sure you have noticed from the other replies in this thread, you really are going to get what you pay for. I paid for a $200 sub, and to me/visitors to the house, i got way more than what i paid for.