I know it's been asked, but I want to replace my RT-12d.  Which is a better perfoemer?  At AVS forum there a ton of SVS fan boys.  I need an honest answer.

will anyone even open the post ?

You'll be hard pressed to find someone who's actually owned both.  There may be someone out there but that person may not have read this post.  I've always liked SVS and have owned 2 of their subs.  They have great customer service which means a lot to me.  The Ultra used in a HT environment is a proven winner on most all counts.

I wouldn't be surprised if your exact question has not been asked on www.avsforum.com.  They have a dedicated subwoofer section, under the Audio section of their forums. Hundreds of subwoofer posts, and I'll bet 1/3 of them are of the form "Best sub: X or Y?"

I wanted input from an impartial source.  AVS forums has alot of SVS fan-boys.

A felow in Finland did a lot of indpendant tests of popular and also some DIY subs. Here is the link: http://www.hometheatershack.com/forums/subwoofer-tests/6015-index-subwoofer-tests-manufacturer-model.html

 I've got an Ultra and wouldn't trade it for much of anything but another ultra.....

RockOn4Klipsch:

 I've got an Ultra and wouldn't trade it for much of anything but another ultra.....

What other subs have you compared it against to come to that conclusion?

All of the fabulous reviews that you've read about the JL's are well deserved.   This is a fabulous product worthy of any audiophile system and so easy to seamlessly integrate with any music system that it's almost magical.  It's a whole nother dimension.  If your an HT  "boom boom"  fan it will do that in spades but it's integration for music is almost magical.