Apologies for getting comic-book-guy on you, but air motion tweeters aren't ribbons. As I understand it, they work on a diff principal, enough that Heil got a patent on the design. Even Sandy admits they don't compare to plasma tweeters, but now that the patent has expired, they seem to be best-in-class, showing up in more and more designs.
I've never heard them, so I can only say the Tritons have over a decade of technological progress in materials and design, as well as a radically different tweeter. The rest you'll need to decide for yourself during auditions.
I have the Triton Two , Center XL, and a pair of def tech 8080st for surround, w/ Goldenear SS60C as a single rear in a approx 2,300 sq ft room used 95% for TV and movies, and was interested to hear what others with Triton Two use for subs - the GE website says the TT2 go down to 16Hz, and they definately add depth and punch that my SVS 20-39CS ported sub has - but not in the league of a dedicated sub -
Do you have a separate sub? If you have a sub anyway - why not get the Triton 7 (or 5's) instead?
With the Triton two - do you still see the benefit of an additional 2nd separate sub?