I've used a TH2G, but only in Eve Online, which is rather low-FPS forgiving. I do agree it would be great for TH in stereo, but I have since realized the advantage of just playing on a single large screen.
The problems with the TH setup also come into play with edge violations at the monitor boundaries, which would also break immersion.
Well, I have a broken lcd and I was going to try and see if i can remove the frame around it (or just the sides) and manufacture something to hold it. That way I could connect 3 without having the bezels in between.
I have heard of all kinds of problems with the th setup, this is how it is with always trying to make something work that doesn't really want to work
(with other stuff that sort of works lol)