I have a Zilla 2x12 rear loaded fatboy cab, it works pretty well with the vh4 for the medium to sort of high-ish gain but for the all out high gain tones the vh4 sounds better with the modern diezel front loaded.
It has a warm and organic sound with a lot of overtones that doesn't sound dull or lifeless. The combination is not a tight as the Diezel frontloaded 4x12 but still way tighter than the Diezel rearloaded 4x12 and sits better in our band mix. I will try some different speakers (mainly G12K100 and V30) for some further enlightenment