I use one. It is a very nice stick, though there are some issues with it. I had to return mine to the manufacturer after all the buttons on the stick quite responding. The problem is that either the stick, or the throttle buttons quite responding the axis work fine. Fortunately Guillemot has a service center in Canada so I didn't have to send the stick all the way back to France. Still it cost me about $40 iirc to send just the stick back.
You might check out this sight;
http://www.warthogworld.com/ some of the issue with Warthogs are discussed there.
I don't have A-10 so I can't say if that setup works in AH. I would think not, unless all the functions use the same commands, which I doubt.
Also, you might want to shop around a bit. I've seen Warthogs for as low as $350. You just have to be patient