B&W asw sub series...

I have been pretty impressed with the latest 600 sub series...very musical, clean, and fairly deep bass at a reasonable price...even the $500 sub in the range is way better than it has a right to be...most subs at this price point are ported, cardboard boxes with fart bass...not so here...any thoughts?
I really like my ASW2500 (10" sealed). Very articulate, but, not very deep. It rolls off pretty sharply as you approach 20Hz. It integrates with my CDMs perfectly for 2 channel.
I'm in the middle of setting up and tweaking my CDMASW sub. I started with the volume at 12 and have slowly backed off to about 8. Too many things were rattling. I used a Stereopile CD and a RS meter. Now I have totally flat at 25Hz. I guess its a little overkill for my room but I don't plan to live here forever. It keeps up with all kinds of music. Better than any of the Polk, JBL, or bose I used to sale.