I'm building both a music-only bedroom system system and a small HT system, so I needed a couple of subs. For the bedroom system, I ordered the Titanic MkIII 10" kit for $288 shipped, but they've been out of stock for weeks and they keep pushing the ETA date out. This will be paired with a pair of NHT Absolute Zeros that are on their way.
The HT system I plan to build out with five Mirage Omnisats. I found this forum a couple days ago and it didn't take me long to hone in on the SVS SB12+. I just ordered a B-stock in piano black. I chose the SB12+ for its size and (from what I've read) ability to do music as well as HT. I feel a little more with a sealed design. I'm really much more into music than HT and would like to occasionally move the SB12+ down into my main music-only system in a (large) living room. I've never had a sub there before, just a pair of Dynaudio Special Twenty-Fives standmount monitors that do quite well down to about 35Hz on their own. I've just sent in my Tact S2150 amp in for an upgrade to XDM status, which adds automatic room correction DSP, so it will be interesting to see the Tact help integrate the SB12+ with the Dyns in the room. The big question is if the SB12+ is going to do much for my large living room (10,000 cu-ft).
I was tempted by the Rocket ULW-10 for about $200 less with the audioholics special deal, but I just couldn't cope with the single RCA input jack and no speaker-level inputs. I wouldn't have been able to use it in my main music system.
I was also looking at the Mirage subs (S12 for $500 shipped), but couldn't find enough user feedback. Also too large.