OK, of the amps I've played through:
If the ONLY thing you want is a face-melting overdrive channel for mega-metal:
Peavey 5150+, or 6505+ as it's now known. Yes, you express reservations about it, but then acknowledge that you're making an apples v oranges comparison. Seriously, get one & a decent cab, stick a BBE in the FX loop &
never look at another amp again.
Engl Fireball the other posters are right, it can & does sound very very good.
Hughes & Kettner Warp-X far, far better metal sound than either of the H&K models you listed. In fact, it's a very bloody good sound. More gain than you realistically need, very tight & detailed with tons of low end. Plus the red backlit front panel looks evil :twisted:
Marshall JCM900 SL-X No longer made, but they do turn up on ebay reasonably often. Effectively a single mega-filth channel with dual switchable volumes (i.e. two of the same sound at different volumes rather than 2 channels). Have often regretted not snapping up one of these when I had the chance...
The above amps are good but have either no clean channel worthy of the name or at least a very limited one. If you want multiple channels, then:
VHT Ultralead I rate the hour+ I spent with one of these things in the basement of Chandlers as one of the most pleasurable experiences of my life :) Absolutely wonderful, wonderful lead channel. Blisteringly hot, tight yet open, absolutely HUGE sound.
Engl Savage
Engl Powerball
Engl Invader Got to disagree with noodle here. The Savage may be one of the older Engl models, but IMO it eats just about everything else for breakfast. It is unbelievable fierce - absolutely monstrous, brutal metal tone. I like the Powerball a lot - really good useable amp with tons of vicious mean overdrive on tap. The Invader is the most versatile of the lot & has some really good gain sounds, but IMO the Savage's Ch4 trumps all in the Engl stakes :)
Mesa Rectifier It's a very popular amp for a reason. The modern high gain channel has a slightly loose "sludgy" feel to it (esp through a Mesa cab) which won't suit everyone, but it's very brutal, very intense & VERY heavy.
Hughes & Kettner Triamp MKII So good are the clean & crunch channels on this amp that CH6 is almost a letdown, but it's still pretty damn good & probably the best EL34-powered mega-filth channel I've heard (as I've posted before, I have a slight anti-EL34 bias for mega metal tones). The closest clip to the sound I heard when I played one is
this so make up your own mind whether that's what you want...