I critically auditioned, side-by-side, a pair of 3.5's against the smaller (and newer) 2.2's at the time I bought my own Thiels five years ago, and in my opinion (which some have taken exception to regarding this subject in previous threads, to be fair), the 3.5's have long since been surpassed in sound quality up and down the Thiel line (guess which pair of the Thiels I bought that day!). Briefly and specifically, the bass is much better integrated, and the rest of the spectrum much smoother and more lifelike, with fewer artifacts and better dynamics everywhere, than was achieved by the 3.5's in their time (although many of the later Thiels were and are admittedly tougher to drive). There are of course many good speakers mentioned above, and lots more others out there, but if you enjoyed your Thiels this long, I would suggest that you not overlook the considerable advancements offered by Thiel models introduced since yours were made.
P.S. - FWIW, I received an email the other day from a fellow Audiogon member (who I shall let remain anonymous unless he decides to join this thread). We had never corresponded before, but having read some of my past posts concerning Thiels, he felt he just had to write to me and tell me about his recent experience. He listed his top-notch system, and mentioned he has owned speakers from ProAc, Avalon, Quad, and Spendor among others. He had just borrowed a pair of the new Thiel CS1.6's from a friend who bought them, and was so blown away by what he heard he could barely contain his enthusiasm. Despite desiring more bass than these little guys can provide in ultimate terms, he seems to be strongly leaning toward buying a pair of these for himself soon. I've heard them at my dealer's, and I don't disagree, though I'll be sticking with my 2.2's for now. Best of luck in your search!
P.S. - FWIW, I received an email the other day from a fellow Audiogon member (who I shall let remain anonymous unless he decides to join this thread). We had never corresponded before, but having read some of my past posts concerning Thiels, he felt he just had to write to me and tell me about his recent experience. He listed his top-notch system, and mentioned he has owned speakers from ProAc, Avalon, Quad, and Spendor among others. He had just borrowed a pair of the new Thiel CS1.6's from a friend who bought them, and was so blown away by what he heard he could barely contain his enthusiasm. Despite desiring more bass than these little guys can provide in ultimate terms, he seems to be strongly leaning toward buying a pair of these for himself soon. I've heard them at my dealer's, and I don't disagree, though I'll be sticking with my 2.2's for now. Best of luck in your search!