$1000 amp

Still looking for a used power amp to drive Virgo III speakers with 90 dB/W efficiency, the following amps are around $1000 or less. I would appreciate any feedback or ranking in order of sound quality from anyone who may be familiar with them:

Conrad Johnson MF2250A (125 W)
Ayre V-3 (80 W)
Krell KSA 50S (50W)
Pass Labs Aleph 30 (30 W)

Thanks