I'm probably one of the former JE 100 mono users that tubegroover is speaking about. I owned RM9 Mk1(serial 016) from late 80's until early late 90's. Roger updated it and I was quote happy. RM9 Mk1.5 was an excellent match wit the Merlins in every iteration Bobby P (RIP) produced.
I then ran down the OTL rabbit hole, first with Berning Zh 270 stock and then heavily modded, unique it every sense of that word, but it could never deliver the dynamic contrasts I feel are necessary.
Couple of years passed, and next the JE 100 monos in Music Wood. Excellent sound, little noisy and fussy but man they delivered musical textures, contrasts & nuances like no other. But then of course there was the heat.....and anyone who's ever owned them understands...yea, the heat...My dedicated room (20x14) 4 months a year (summer) was unlistenable. Windows open, fans, the AC was the only cure and even then still very, very warm.
The JE needed service. Jud was in transition and my original idea was to purchase a MR RM 10 as a 'summer amp" to drive the speakers and use while Signature Sound serviced the JE.
2010, I Called Roger, the RM10 "sort of" worked but not well with the Bam in the circuit. Roger had a rebuild of RM9 Mk II and a RM9SE available. I auditioned the SE and immediately was seduced with its magical midrange, effortless reproduction and its solid well built quality. Mark that amp SOLD!!
After the JE 100 came back from repair from Rich at Sig Sound, I A/B the two amps over the next 10 months and the JE were put up for sale and sold quickly. 8 years later and I couldn't be happier back in the RM9 camp. The SE is a statement piece. Hand built like a fine watch, point to point wiring, hand wound transformers and a way to check each and every tube with a volt meter to trouble shoot if there are any issues. Built to last a lifetime.
If you made it this far, thanks for reading!