I have owned a few modded Marshalls including 3 or 4 Cameron modded Marshalls. The Camerons are killer but to my ear and the way I play, I prefer a stock Super Lead circuit and I "mod" it with a Boss SD-1 or a Boss OD-1 or a Boss GE-10 or an MXR 6 Band EQ, or a Tube Screamer or with a strat I "mod" it with a DOD OD250. Every single one of them has a slightly different flavor of modded Marshall sound to them.
I had a more modern built "Jose" modded amp that came from another country and the owner is the nicest guy in the world so I won't say what brand, but I could not get rid of that thing fast enough. The diode clipping sounded so synthetic, like the distorted sound a kazoo makes when you blow into it hard. I messed with it for weeks and it would give me ear fatigue within about 15 minutes every time I played it. I could not sell that thing fast enough!