I just wanted to join the choir of praise.
Pianoteq 6 is great. I just did a fairly detailed comparison with the Garritan CFX. Pianoteq is in many ways better, and certainly a lot more versatile. The CFX has a really beautiful tone, but nothing that Pianoteq 6 can't match. Any differences in timbre are now a function of a difference in kind of piano, not quality. And Pianoteq's overall sound is much more organic and integrated, with much more sonic bloom, far superior sympathetic resonance et cetera.
The biggest surprise for me was the YC5, which I always found largely unusable, but which sounds great now. Both the Steinway D and B are great and significantly improved. I'm really taken with the Grotrian Under Lid preset: a really weighty, visceral sound.
I've probably reached the point where I'll now longer use any sampled pianos. I'm glad I first bought Pianoteq more than 10 years ago, when its potential was already obvious, though it still had many shortcomings. My faith in Pianoteq and in the Modartt team has been more than justified.
Pianoteq is now a technological marvel: elegant, incredibly versatile, super playable and realistic-sounding, and made by a team of supersmart people. Compared to this, sampling is just so cumbersome, unwieldy, unsophisticated, and just plain dumb.
In short: congratulations to Modartt, and to the community of (virtual) piano-players!