Opinions on Graaf Amps

Does anybody have any expereince with Graaf OTL amps? I'm especially interested in the little GM 20 but don't have a chance to listen to it where I live. Has anybody heard it? In my search for a new amp I have listened to the Carys (572s) and found them overall too bloomy. I don't like tube amps that try to sound like solid state (i.e., Audio Research or BAT) but I also don't want the tubes to color the sound too much. I've tried the Atma-Sphere S 30 which sounded terrific in my system, open, airy and very musical, but it just runs too hot. So now I am considering the Graaf or perhaps an Air Tight. Any thoughts would be appreciated.

My system:

Joule Electra LA 100 MK-III
Merlin VSM + BAM
Audiomeca Keops as transport and Audio Logic 2400 DAC
JPS Super + speaker cables, FX interconnects, and Power Cords

Many thanks,

Dr V