I am getting ready to pull the trigger on a pair of HSU ULs-15's. Anyone have any experiences, good or bad, with these? They are 2300.00 for the pair if anyone can compare other subs in that price range.
Rythmik 15 HP.
I bought a pair of them last year when I upgraded my active speakers. I love them. Build quality is top notch. Rosewood finish is perfect. The ULS-15 is a good size; not too small to be just a distortion generator and not too large to be a pain in the butt to move around.

I've owned subs from M&K professional, SVS and JBL professional. SVS didn't have a sealed sub with balanced connections when I was looking, so I took a "chance" on Hsu. No regrets.

I've not seen any serious measurements of the ULS-15, but based on driver size, cabinet size and amp I suspect it performs well.
Measurements of the ULS-15 by John E. Johnson...

THD+N looks good until you realize the distance is only 1 foot instead of the typical 2 meters.
If you are looking for a accurate subwoofer for music first, movies
The New JL Audio subwoofer is Half the price of the Fathom models
The E -110 is $1500, and the E-112 is $1900
And much more accurate JL audio has been around for years
In your car who is top ? JL Audio, in High end Audio JL most allways wins the awards.the other brands are still very good . Rel models over $2k
Are also very good as well as the Velodyne DD plus series but also much more $$ and no better then the JL Audio.