Well... difficult question and I cannot say I am the one to answer it because I do not have extensive listening with any of the above amps and then there is always the problem of system/room effect on the particular amp. I will make a comment because it seems you have narrowed down the field without ever listening to any of them which I think is generally not a good idea.
Generally, I do not think the buying the "next level" of anything helps much because there isn't one. There is no "absolute sound" despite what the magazine cover says. You can go up in price but that doesn't always help either. A lot of the really expensive stuff is sad indeed. There is a post right now at madisound.com about some speakers that retail at $90,000 and they are a joke.
Why not just buy what sounds good to you?
It looks like you are considering some "exotic" amps. The typical OTLs are nice but they are not new and like anything else have their compromises. Bernings OP stage is apparently new and I must say I do not understand the radio frequency impedence converter that replaces the opt in the output stage and probabaly few people do. He is obviously some kind of a genius. However, despite the OP stage's novelty the amp relies on other design choices that you may or may not like. The drive stage, for example, uses a cathode follower directly driving the power triode grid, which technically seems great, but is not new and at least some folk think this circuit design choice imparts a certain sound which you may or may not like. The OP stage is not going to change this choice of driver design. The point is that you cannot really buy an expensive amp because it's output stage is newest in town. Well you can, but I am not sure it's a good idea.
It's late at night here and I tend to babble a lot the later it gets.
Cheers, have fun with the new amp whatever it is. Hope it Sounds good to you.
Sincerely, I remain
