Anyone running a Sumiko S-10 subwoofer for music? Impressions? How about Hsu ULS-15?

I have considered both these subs. On paper, the Hsu ULS-15 is the clear winner. But the Sumiko integrates perfectly, according to one reviewer (S-9)
I now have a Rel Storm 3 in my system which I have enjoyed for many yrs now. I have a rather large space to cover due to an open floor plan with 15x20 LR w vaulted ceiling opening to 12 x12 DR with std 8' ceilings. I love the way the Rel integrates in my system and don't want to give that up. This has me looking at others in the Rel line. However, Sumiko, (which was the Rel distributor for years) also makes subwoofers with similar specs and size. This causes me to believe that they have much in common with the Rel and at a better price. The Sumiko S-10 has 12" woofer (down firing) with 12" passive radiator (side firing) & 500 watt class D amp. All the other Sumiko S series are similar to the T series Rel. However the S-10 has similar components and specs as the Rel S-5 SHO which gets very good reviews. So I am considering jumping on the S-10. But I cannot find any reviews on the S-10.  Thus my post 
Anyone with experience with the S-10? I have seen many Hsu ULS-15 reviews, mostly from Home Theater users which leaves me questioning its musical integration ability. This leaves me leaning towards the Sumiko S-10. Thoughts?
BTW, main speakers are Silverline Sonatas (Avalon style)
my good friend recently got the s-10 to use with his magnepan 3.7s and i was genuinely impressed--the sumiko was very fast and integrated pretty seamlessly; seemed like good value. i haven't heard the hsu.

Thank you. One question if you please. How big is your friends room? Is he using one or 2 subs? Thanks again for your help

his room was fairly large--i'd guesstimate 15 x 18 with fairly high ceilings. he has only one sub and his is a music only system (not movies)

Thanks again. My system is music only also. And my room is similar in size except it opens to a DR . I'd like to do 2 subs but considering it is my living room, placement is not easy & WAF further complicates placement. Then there's budget. Purchasing 2 is going to put me in the doghouse. (>:
Absolutely do not go with that HSU for music.  I had one and it’s a great sub for what it is, but it wasn’t exactly musical and tight.  Sumiko would be a way better option.   And JL a better option on top of that.  Look for a D110 from JL.  Simply amazing for the money.

Thanks for your input. I considered the JL until I read a review wherein the reviewer said he had run dual JL's and thought the JL to be the best  for music until he got a Rel S5. Of course, that's just one man's opinion. But he had experience. If I had the $$$ I'd try all the top contenders
Hello All. New to the forum, happy to contribute what I can.

I bought a pair of S.10's almost a year ago after removing a couple walls thus increasing the room size. Went from one smaller Rel to the pair of Sumikos.

I put them where I wanted them to be based on looks and educated guessing, tweaked a little, was happy with the outcome and have left them there ever since. I run them in stereo so each is dedicated to their respective channel.

My room is 23' wide x 25' deep, with a vaulted ceiling rising to 10-1/2' high. I easily forget they are there, which is a good thing. I simply enjoy how deep they can go and how natural everything sounds. Then there's what they can do for my Movie Nights, . . . . Wow!! 

I've been very happy with this purchase, even with one issue that I haven't put any time into solving. If I use the Neutrik cable I get a faint hum. In the past with the Rel it turned out to be the Comcast coax that I needed to run through my power conditioner. I confirmed through Sumiko Tech Support how they recommend connection with my Krell amp, the hum is still there, but I really think the source of the hum is elsewhere in the system, I don't think it's the subs. I'll get after it someday. (The Krell is on its own dedicated circuit with isolated ground, the subs are each on their own dedicated circuits with a shared but otherwise isolated ground).

Hope this helps.

Welcome  to the forum. Thanks for the info on the Sumiko S-10. FWIW, i have ordered the S-10 which should arrive Monday. Afterwards I will try to give my impressions
@ttocs I now have 2 of the Sumiko S-10's. Fantastic subs. Goes deeper than my Rel Storm 3 which was a great sub in its day. I too had a hum which I had to overcome. I found the fix on Rels website. It was not the cable coax in my system. I can tell you how to fix it if you need the fix. Give me a shout if its still humming.
Like you, I'm very glad that I bought these.
I currently have an S.9 which is being powered by a Rotel 1592 purely for music. I'm planning to add one more S9 which I will use for movies and partner with S55 Polk Audio floor standers. My AV space is about 25-30 square meters with low ceiling barely 6 feet in height as it is located in the attic. Do you think it is practical to add one more Sumiko S.9 and run dual subs for music? I've heard the SVS PB/SB 1000, Polk's HTS, B&W AW610XP, but I went for Sumiko S.9 as it really performs in par with a Rel T9i which unfortunately is beyond my budget.