If WAF is the priority then the 400 has few rivals anywhere, though the also small sealed excellent sounding Fathom JL113 would be up there as well, but it costs 3x as much. You really can stick this small guy just about anywhere and it will be heard and not seen. The 400 sound is very detailed and tight ( I won't use the term "fast" because all the engineers I know don't like that term, but both "tight" and "fast" refer to excellent handling of abrupt loud transients). If you don't need the high output of the other EP subs, then its a great choice for small rooms or if your listening habits are at lower volumes.

John