I played a Dmoll last weekend. Got to spend some quality time with it. Amazing modern sounding amp. Really versatile too. It has the crisp, detailed trademark Diezel tone for sure. I liked it better than the Herbert, no question, and it may have slightly edged the Fokker. Depending on the cab I played them through, the Lil Fokker and Dmoll were close for high gain. I think the VH4 is still my favorite Diezel but the Dmoll is right there with it and can maybe get a little more aggressive.
I've spent a lot of time with the 101b as well. They are so different that you'd be completely changing everything about your tone if you switched it up. The Bogner has that gooey compressed tone that sings on leads and the epic blue channel tone. The Diezel is open and has a more "clean" clean channel... The Diezel is harder sounding and more raw in the feel, meaning the give that it has when you dig into a big chunky chord or palm-mute.
IMO,
Bogner = finesse for lead playing, amazing blue crunch tone, good clean tone but a bit murky, high gain rhythm tones are decent.
Diezel = More clarity, holds together better for tight high gain, better clean, harder feel.