Did not know Vandersteen made any amps!
Every system I've ever heard with the CAT SL-1 was amazing, and those mated to the CAT tube amps have been mind blowing.
My Four Favorite SS Amps
The best SS amplifier I've ever heard was a Vandersteen driven by a CAT preamp. Amazing. I almost never bring it up because it is so far out of my price range.
The next three are about the same IMHO for sound quality, though the Ayre stands out a little.
D'Agostino, Luxman and Ayre.
Honestly the D'Agostion and Luxman sound very close. Tremendous bass and treble extension without hardness or accentuation. They just make speakers sound much more capable. Very smooth, dead quiet.
Now Ayre... Ayre is also very good but also IMHO kind of different sounding. It makes the room seem quieter and darker. I do NOT mean dark as in it lacks treble, not at all. I mean, it's as if you are listening into a pitch black room from which notes just magically come out of. It is my favorite? Should you get one? I don't know.... I really like the sound.... but it's ... just different?