Ok, so I had a couple of hours spare this afternoon so I though I'd compare a few amp sims.
I own and have been using Guitar Rig 3 and 4. I downloaded Amplitube Metal demo.
Here are some demos:
Amplitube
Guitar Rig 3
Guitar Rig 4
I've only used default presets. I think the pick attack sounds best on the Amplitude sim.
Opinions?