I have a TechnoTrend 3600 USB. It does S2 just fine (so far) and even though it lists a max SR as 30msps, I've locked channels that were above that (altho not by much, 32,something)
I've watched quite a few HD channels (both S and S2) and haven't had any problems with it (at least nothing above and beyond what others report about locking S2 signals)
now, I can't compare it to anything else, as I don't have anything else. But if you have specific questions or would like info about this particular unit, ask away.
I can't remember exactly what feed I watched, nor would I be allowed to post it here anyway, but it was full 1080P and AC3 and worked just fine on my Dell XPS laptop.
I think audio was a few meg/sec and video stream was just under 30.
like I said, if you want to know something specific to this model, let me know and I'll check it when I get home (except tonight that is, have class and then a school board meeting)