I'm loving this sub, its a step up from my old JBL 10 inch, and its price is a little lower too... Sound quality is very nice, and the frequency range extends very deep, I know quickly if there is too much going on deep down when I feel vibrations in my chair! (I have it calibrated in my system using sonarworks)
This sub seems plenty powerful for my medium sized studio paired with KH120a monitors.
One thing that bothers me is the power saving mode... Lire plus
I switch to another set of speakers, and when I come back to my sub setup its often shut itself off and i have to wait a few seconds to wake it up again (which will then pass sound thru to the main monitors again). Its not the end of the world, but if I am switching back to make a quick comparison, this can kill the vibe a bit. Sometimes I just want to listen to something quietly without making much noise (imagine late night and you don't want to disturb anybody), but the power saving forces you to exceed a set threshold to wake it up, which can be louder than desired when it all pops back on.
It is an excellent budget friendly sub, it has me impressed.