I previously bought a 215 to use temporarily before I purchased an SVS. As you mentioned, it performed exceptionally well for the price ($99.00); a good return on the money.
Initially there was a noticable element of boominess but I solved this by placing about two square feet of plywood between the carpet and the sub.
As I think about this a little more, I think I paid $149.00 at that time (about two years ago) so it looks like you did well on price!
-GeorgeM