I can compare the Ace to a 50W JCM 900 Dual Reverb . . .
I have an Ace head running thru a Stilrtto/Trad 4x12 and he has a JCM 900 with a small circuit modification (treble cut, bass/mid boost).
the 900 can't come close as far as cleans go and it gets stomped by the Ace when it comes to the crunch tone. The Ace beats it in the hi-gain department too. Much more gain on tap.
Overall, the Ace has a smoother and more harmonically rich overdrive too.
Now, I still like the 900, seriously. But it's very much a one trick pony in my opinion. It does the 80s / early 1990s hard rock tone very well but it can't do much else. With only one EQ for both channels, you're really limited too. I don't mind the clipping diodes - it still sounds distinctly Marshall just with a little more compression and a little more bite. I'd get one as a fun project to modify and get some cool tones out of but I'd never use one as my go-to amp. Not versatile enough to be a good all around rock amp and not clean/pure -sounding enough to be a classic, low-gain, crunch-tone amp.
