SVS Subwoofers for music?

How good are the SVS subwoofers the cylinder series compared to the REL B3, Martin Logan Depth & Dynaudio sub 350 for music? The SVS seem to be a great value. My room is small 11x15x8. Thanks for any input.
Dynaudio Focus 140's
Plinius 9200
Naim CDP 5i-2
For Movies NAD receiver T762
All FMS cables.
You get what you pay for.SVS would be cost effcient for HT but muisc a multi driver sub will better it.
The SVS subs are capable of producing clean bass at high SPL. It's quite possible that you won't need as good a sub as an SVS for music.
SVS' SB12-Plus is a very musical sub. That is a welcome departure from SVS' previous, build a bigger box and driver to win dB "drag races" to impress the HT crowd, efforts. The quality of the upper bass was lacking in the older SVS subs, IMO.
OK, I bought the new SVS PC13 Ultra recently to match with Magnepan 3.6R's and for home theater. I knew that the SVS would be great for home theater, and although I really only wanted one sub, thought chances were high that I was going want a second "fast" sub for 2 channel. When the sub came, it was great at moving air with fantastic depth, but I couldn't really get it to match with the Maggies, so as I had resigned my self to the fact that I was going to have to buy a Rel, Velodyne, Vandersteen, or the like for to match the front end. As a last ditch effort though, I bought the Velodyne SMS-1 equalizer and that turned out to be a stroke of accidental genius. I was able to then quickly integrate the sub with the Maggies, and still get HUGE air movement for movies. I couldn't be happier. I really like the SVS product. They need to charge a bit more, and include an equalization system, or breakdown and pay Velodyne for theirs. Huge improvement.
Macdadtexas, thanks for posting your experience. Some of the SVS products have a single channel of analog (I guess??) PEQ. The SMS-1 is a great product. You would have needed it regardless of which sub you bought.
The SVS SB12-Plus looks very interesting. Has anyone had direct experience with this sub? Is it at all comparable to a REL B3 or others in the B3's price range? If so, it would be quite a value at less than half the price.
I intend on ordering an SVS SB12-Plus for my office system. I've been impressed with the independent measurements of their subs, the outstanding educational information I've received from Ed Mullen with SVS and the feature set of the SB12 makes it a good choice for my office. I'd like to get my M&K MPS-5310 sold here at audiogon first, but I may not be able to wait.
I have a SB12-Plus in my office.

I found my friend's REL B3 in his home to be much more impressive.

The small size and price of the SB12-Plus was attractive.
Thanks for your responses. Bob, could you please post your impressions if you follow through with the purchase? Thanks,
Will do.