The EVH cab is probably the best greenback cab around, and the 5153 just sounds great through that. I guess it's an integral part of the sound. For a gigging musician the 3 completely separate channels are the bomb.
Big fat heavy can be a lot of different things and most of them can be achieved with this head.
Clean is really a Fender clean, but turn the gain up and it is AC/DC. Weird but kinda cool. Can do from country to classic rock with ease.
As a core sound on blue channel, it sits between the BE100 and the SLO. Not as "refined, snarly but warm" as the BE, but not as grindy and tight as the SLO. It's a classic sound with a touch of modern. Love it. It has enough gain, it can feel lacking for some guys at low volumes, but so does a modded 800.
Red channel is pretty much the old 5150 high gain sound, but it's not fizzy at all, unless you turn the presence up. Dial them mids out, crank the presence and there you go, modern metal.
That 3 presence knobs are the most important tone shapers of that head.
Effects loop works good, transparent and clean. Some folks had issues at bedroom levels, not having enough signal. Dunno. Never met that issue.
Tried a lot of versions of the Peavey 5150 but never bonded. Yes it can be brutal, but that's it.