I have a ML 5805 paired with a pair of esl 11a and it is a very nice match. Very clear sound, more pure than something like a McIntosh, IMO.
I do not see a problem buying vintage as ML equipment is very well constructed. Just be sure it is in good condition and well maintained.
I bought a pair of 11a's this spring. I have been using a Mark Levinson 8505 and I could not be happier. Built in MQA DAC and at 4 ohms your getting around 250w. I have had no clipping at higher volumes and have not set off any protection.
Expensive unit, however, you can find some open box...