advice about Cary & McIntosh needed ...

A Watt (W) is a unit of energy per unit time. More specifically, 1 W = 1 Joule/second, where 1 Joule (J) = 1 Newton meter (N m). Thus, 1W = 1W and it is not possible for a tube watt to be "somehow stronger"! Now, it may be possible for the advertised energy per unit time of an amplifer to vary, but that is largely a quality control issue associated with the producer.

Buy the MA-6900, sit back and enjoy...

I would like to try to explain how a tube watt is stronger than SS watt. The rating of an amp usually shows continious powes using pure sine wave signal. However, the music is not pure sinewave. At low freauency and when signal is not clean-pure sinewave - transistors and other SS devices go into satiration mode and overload. Many SS amp can't handle that. So they need much higher power just so they don't overload during tough music passages. Tubes don't have this problem - if they rated at 20 watts, they can handle 20 watts of most any signal. So can some of the better made SS amps that have vary conservative ratings based on true load. So amps like 100 watts rated Mc or 30 watt rated NAIM behaive more like tube amp due to their conservative rating and abbility to handle tough loads. I hope this helps. Otherwise, just trust your ears and enjoy the music.

Regarding physical units lecture I had 5 years physics course in high school and 3 years electronics course in high school so I quite familiar with them :)
And besides all this knowledge I heard 50W tubs amp playing louder then 100W transistor equivalent. This is what I have meant by stronger watt.
What I did not have in school is possibility to compare great amps hence my question for advice about it.

So any insight about Cary V12 vs 805c and Cary vs McIntosh 6900 ?

I listened to the Cary V12 for a long while one day playing big Soliloquys (6.3 I think) and it sounded very good. I also heard a Unison Research 845 integrated playing Royds that sounded even better - downright impressive and bizarre. I have also heard at length a McIntosh 6900 playing Vandersteen 5 that was to die for. Actually, it was the most versatile sounding of the three systems (I heard them all about the same time) in that it could really handle wall-shaking bass and the vocals were still beautiful and liquidly real. The layering was incredible and gave a sense of amazing coherence. Anyway, if one day I want to trade-in my little McIntosh separates, I may have to get a 6900. I just love it.

Depending on your taste in music, this may or may not be the case for you too. You will have to experiment and see, but afterall, that is a large part of the fun. As a final note, your Thiels will like the McIntosh's effortless power very much. Good luck! Arthur