I have Thiels and a CAT hooked up. But I listen mostly to classical and jazz. I have auditioned the Electa's, Electa Amtors and Extremas. The Extremas are far and away the best of this bunch - but oh that price tag. The SF are definetly in a class by themselves with respect to the richness of the midrange, the smooth but accurate highs and superb imaging. Not much in the bass department though, except for the Extemas. But the Thiels' overall top and bottom end, dead accurate frequency range response and transparency outdid the other SF speakers IMO.
If you go with the Sonus Fabers, you will miss out on what is a Thiel strong point - the initial transient (step) response. This gives a lotta push and pace for jazz and, especially, classic rock. The SF's will "slow down" the pace for rock and jazz, make them sound polite and refined. They will, however, give you that natural warmth, tone and balance that is, IMO, essential in classical instrumental.
EIther way, if you are looking for a "sweeter sound", the 3.6's and the 7.2's will, by far, be a bigger improvement over the 3.5's. You have a not-too-shabby front end there; the newer Thiels will give you much better perfomance with respect to rock and jazz. The SF's will give you a much warmer sound - but I don't know how that will square with rock. I would probably take the 7.2's over any SF speaker.
If you go with the Sonus Fabers, you will miss out on what is a Thiel strong point - the initial transient (step) response. This gives a lotta push and pace for jazz and, especially, classic rock. The SF's will "slow down" the pace for rock and jazz, make them sound polite and refined. They will, however, give you that natural warmth, tone and balance that is, IMO, essential in classical instrumental.
EIther way, if you are looking for a "sweeter sound", the 3.6's and the 7.2's will, by far, be a bigger improvement over the 3.5's. You have a not-too-shabby front end there; the newer Thiels will give you much better perfomance with respect to rock and jazz. The SF's will give you a much warmer sound - but I don't know how that will square with rock. I would probably take the 7.2's over any SF speaker.