I had the PB12-nsd and found its frequency bump around 50-60hz over emphasized things too much for my tastes and I upgraded to the PB13-Ultra which is has a nice flat FR like most DSP subs. My wife wants to use it as an end table(no HT room for me either) as it is too big for her tastes but I like it too much to get rid of it, at least for now.
I can second the thought of the Paradigm DSP subs. I compared the little 3100 to the EP350v2 and v3 and the little 10" sub was much better than the old EP350v2 but couldn't move enough air to compete with the 12" driver on the EP30v3, although the 3100 was still reasonable for HT it was great for music. I would suspect the 3400 would be in the same output range as the EP350 or even the EP500 which is quite an astounding performer from such a small box, well as far as sub boxes go anyway.
