Let us not forget that the HiAmp comes with a matching 4x12 that models (as best as I understand it) the old HiWatt cabs with Fane speakers. That makes this cab model a little special alongside the vast array of Celestion-oriented cab models.
I was trying to fake up an early Iommi tone using either the JH Gold or British S100 in place of an old Laney head, with the HiAmp 4x12 for the cab (since Laney cabs also used Fanes back then). I was also twiddling with the Diode Overdrive pedal model in place of the treble booster.
Those are pretty big kludges
but on the other hand I felt like I was getting acceptably close to a
Paranoid-type tone.
Anyway, I think the HiAmp model is great -- well worth having for those who dig the classic tones.
Very much a '70s Brit vibe, but with a flavour distinct from the vintage Marshall and Orange models. Lots of clean headroom, and takes the pedal models well, IMO.
The ENGL E650 does look intriguing ... one of the relatively few pieces of gear that I haven't got but do actually think about getting
but I haven't tried it! I have to admit that, at this point, I'm kind of hanging out to see what happens with the semi-mythical Amplitube 4.