You might want to consider a Bakoon amp.I compared my AMP5521 to the Leben CS600 a while back and preferred the Bakoon.The Leben was very good but the Bakoon was clearer and even more musically communicative.The Bakoons are not tube amps but they are like SET amplifiers in that they are current driive/high output impedance/no negative feedback and to me sound more like a good SET.A really good SET.And a half decent SET should sound better than a really good push pull tube amp.I owned an Almarro 318B which was modified and sounded better than the stock version and which did sound good but honestly even the base 15 watt Bakoon SCA 7511Kk 3 sounds better.A bit similar but better.
I can't speak to which sounds better, but if you're looking at Atma-Sphere as a possibility, its the M-60 that would be the candidate. The Devores are easy to drive and an extremely good match with our amps. The M-60s will make about 60 watts on the Devore.
In your price range you'll be looking at a used set of M-60s. BTW, older units can be fully updated to the latest version with full warranty reactivation.
The Raven Audio amplifiers will absolutely outperform all of the amps mentioned on this list. Amazingly enough they actually guarantee that in writing. Call Dave Thompson and talk to him. It looks like all of their Avian integrated amps are below your $5,000 budget point. Read the Florida show report here on Audiogon by BlindJim. Its almost all about how good their room was.