Hi,
I have a ENGL Savage 120 and it's an excellent amp, no doubt about it. But now I'm looking how to change the sound, probably by changing the tubes. But I really know it well, that's why I'm not so optimist. But it's excellent, and very versatile.
For me, it sounds thrash metal, "old school", and very aggressive.
The other guitarist of my band uses a powerball and I prefer it, it's more death metal, but not precise enought, sometimes.
ENGL amps are very good but they dont' sound allways that good on stage in the mix, with a mic. Well, it depends... I saw The Haunted with 2 powerballs and the sound was huge.
I tried the Überschall, and I've been very impressed, but too expensive! And I don't know how it sounds with a band.
Take a look to the VHT, they are also very good.
And for my part, I don't really like Mesa, but I had a "not very good" experience.