Thank's for all the info.
Had Revox B77 mkII and A77 (both in great condition) in for the test. Both 7,5 machines, unfortunately... but... I tried both and A77 has some special sound that B77 does not have... B77 mkII seems nice and clean, but lacks some "mojo". A77 is much more funky.

Is that a common observation?
I can also get a pro version A700 with 15ips, so I guess I'll go for that or some Studer A810 in the future for mixdown, but right now I got the most realistic "tape saturation" plug-in for 130EU.
What does influence wow and flutter the most - the condition of the tape?
Just another question about that mod - there are several inputs - does the AUX input also pass the mic preamps? Can someone please post the link or description how to do that mod?