I recommend you do a home demo of Classe Delta Monos only if you are 100% sure that your cabling is not your bottleneck. Alot of people will tell you that cables and amps don’t matter but they absolutely do when you are building a system of your caliber. Now I do not believe in cable burn in as every cable that I’ve added through my upgrade path, I’ve heard an immediate difference.
Back to the Classe Delta Monos - My previous amps were the Parasound A21, Audio Ref 75 and 150SE. I still run a Ref 6 and Ph7 in the pre but with 600 watts in 4 ohms it really pushes my system.
Michi M8s as mentioned do not have the finesse on the top end like the Delta Monos and are more bass heavy. I got off the tube power amps wagon because I was racking up to many hours on tubes and the replacement cost is not worth it in my opinion with the cost of power amp tubes these days.
The other solid state amps mentioned are all very nice but more than double the cost of the Delta monos for only marginal gains.