Well, I have heard a W7 set up, it wasn't terrible, definitely loud and sounded ok, but the idiot running it had no clue what he was doing so he was distorting the hell out of it, clipping the amp, using bass boost and all that dumb stuff. My 2 Stereo Integrity BM 12s were around 10 dB louder on the meter and sounded much better, but again, the W7 was not nearly optimal.
I think there are definitely subs that sound better than the W7 and can match it in linear stroke, I haven't ever owned any of them though but the old RE XXX should beat it, the new XXX should, the LMS drivers should. The Acoustic Elegance AV line should put up quite a fight for much less as well.
For pure SQ the W6 is better, I would say the Mag V4 is better, probably some ID subs too, but I have never heard ID.
In closing, the W7 definitely combines some great qualities, and if you get it for a decent price, there is 0 wrong with it, and even the other subs that match it can be similar in cost ie. the XXX and the LMS.