You're right Grandarf - I won't let jewel ruin my fun.
The Touch's analogs are are indeed rubbish, though, I won't go back on that one. They'll give you music, but once you hear how much better the Touch can sound you'll likely react the way we did. Just my opinion, of course.
To answer your question, there was not a huge margin of difference between speakers IMO. At this point you're into that "point of diminishing returns" realm. There were clear differences and better attributes between speakers, but no speaker was destroyed by another speaker.
As far as the Ascend Towers, they are leagues above the Sierra's (I only heard the originals, so I cannot comment on the newer ones). The midrange is more detailed and resolving, the highs aren't lacking extension and detail anymore, and the bass is supper punchy and has nice extension for such small drivers. They also throw a much larger soundstage and have more precise imaging over the Sierra-1s. If you're thinking of making the switch you should definitely audition them first if you can, but I think you'll really like what you hear. Since Dave offers a trial period I'd say you should give them ago if you want to try another Ascend product.
Dynamics: The Sigs are much easier to drive and can get a lot louder than any of the other speakers. Obviously Paradigm felt this was an important design attribute, and they did a great job in this department IMO. There are things that they other three speakers did better, though, so it all comes down to which trade offs you're willing to live with. Do you want extreme dynamics, absolute clean resolution, wicked bass, ultimate transparency, etc? You've got to decide what you like, then choose based on that. As I mentioned yesterday, no one left the GTG feeling as if their speakers were inferior. I'll happily keep my ST's, unless Terry wants to give me his HT2-TL's for them, and I'd be willing to bet the others would say the same about their own speakers.
Rather than do a review for every speaker, perhaps we could just do a Q and A. Ask us what you want to know and we'll be honest about what we heard, even if it means getting harrassed by some folks via responses or PM's.
But please, just remember they are only our opinions and they may not apply in your situation and/or different rooms. Do not buy speakers based on other people's opinions.