Until recently the overhauled/twealed AU-X711 was my main amp, but the 907DR and now the 907XR are the kings of the room.
The 711 hasn't been used for a while. The AU-X701 runs my outdoor speakers. The AU-719 is immaculate and fully overhauled too, but it doesn't get used these days - it is for looks only. Same goes for the other Sansuis in the room but out of shot.
To me, all of the alphas sound better than the 719, and likewise they are better than the BA/CA-F1 combo and also the AU-20000. The late model 907s are just fantastic.
I haven't heard a 707X as they don't come up for sale in Australia, and it's a lot of effort to import them. People tend to head straight to the Alphas instead.
I've heard the AU-D11 and AU-D11 II, and both are lovely amps. The D11 in particular is a great choice for someone wanting a bit of the clarity that the late model Alphas bring, but with a bit warmer sound and the old-school looks. I still prefer the Alphas though - they are more transparent and accurate to me.
It's very hard to rate amps on a scale - what is a big difference to one person will be tiny to another. The system also makes a difference to your perception - different systems do different jobs of highlighting the similarities and differences between amps. Whenever I go back to the older Sansuis I quickly realise what I am missing out on. They still sound lovely, but it's like looking at photo which is slightly out of focus vs a really crisp image (again, in my opinion and experience).
Most importantly of all... any comparison between amps MUST be done with exactly the same output level, otherwise you are not comparing apples with applies. Testing with, say, a 1khz tone and either a calibrated dB meter (preferred) or an app for a phone will help. Variations in volume levels will trick your ears. A fellow AKer pointed this out to me recently, and I agree 100%.