I've been playing AH for about a month now with two monitors (@2560x1280).
I have a AMD XP3000 (1.6GHz) and 2Gigs ram driving an ATI X1800XT.
I get a 50-60 FPS in all conditions (I have Vsynch enabled, natch). Performance is more than acceptable, and I would expect driving an extra monitor with Triplehead wouldn't hurt that much.
The main problem, as mentioned above, is that the field of view is messed up in AH. It zooms everything in to keep the FOV constant. I wish Hitech would work on fixing this issue - or at least telling us how to work around it.
But I imagine that would lead to lots of people using a fisheye (FOV >180 degrees) and others whining about it.
This isn't too a big deal if you use a TrackIR (I do), but without that - there will be gaps where the views do not overlap. That diminishes the utility of the TH2go.
Diche