I traded the MK IV for a Les Paul about 3 months ago. It was a great amp but i was in the market for a Les Paul.
On my 3 channel DR i use the orange channel like a classic rock tone then the clean & red [red for modern].
Don't be fooled by the single Rectifier the modern mode is a beast and loud af. Clean is adequate.
Single Rec for 50 honest watts is about 25 pounds lighter to carry but still all Rectifier.
I traded a MK III combo for the single Rec.
Loved the MK III but was hard to lug around and the guy traded to absolutely loves it and i wasn't playing it much anyway.
I would still have the MK III if it were a head.