Most Musical Subwoofers?

I was wondering if any one had used/heard the Legacy Audio Extreme HD? Anyone compared these to JL Audio F-113 or F-112s? I'm considering adding subs to my system as my room has a suckout at about 40 hz that I'd like to fix.
Thanks in advance for any info/experience you might have. I'd be glad to discuss/talk over the phone as well. Send me your phone #.
Good listening,
Steve