I was using a Zesto Leto with the Mid Monos. That caliber of preamp really demonstrated how good those amps can sound.
I used them with a CJ Classic 2SE and that was a really good sounding combo. Also used them with a Sonic Frontiers SFL 1 , sounded great.
These amps are way under rated in my opinion
I used them with other gear short term , McCormack RLD 1 wasn't a good match, sold that for the CJ