Well I sold my Ultras and switched to Ascend when I found a pair of Sierra 2s on Craigslist for a hell of a discount and was very impressed. The Sierras I have use a different type of tweeter, a ribbon instead of a dome and are known to be very smooth and detailed, and that is indeed what I found. The Ultras are very good, and I'd be happy to have them still, but I liked the Sierras just a bit more. I wouldn't say the difference is night and day tho. I think the Sierras are just a bit more refined to my ear and I was suffering pretty bad from upgrade-itis so I wasn't really in control of myself...
I've only heard Ascend's ribbon speakers tho so I can't really speak for the HTM 200SEs. They do have a forum I post on occasionally tho and a few guys that are happy to answer questions like this. Dave, the owner of Ascend Acoustics pops in there fairly often too.
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