OK Softh is a great solution for some games. It has no res restrictions (within reason) and you don't need to pay for it.
But TH2Go fools your PC into believing the 3 monitors is one so it is a hell of a lot easier to get to work on games, the supported list is quite long. If you are a one game charlie and that game is supported by SoftH AND you are happy to do some tweaking then yes you have wasted your money. If you want to play lots (but certainly not all!) games in surround then TH2Go is the way to go... just IMHO obviously :)
have a look at the TH FAQ http://www.widescreengamingforum.com/wiki/index.php/TH2Go_FAQ
Actually after using SoftTH for about an hour... it's not good.
found some problems with it:
1) It's software based so it takes up CPU cycles
2) don't really work with all games (but then again I don't know how much better/worst compatibility is to the actual hardware thing)
3) it seems to limit my fps to about 25-30fps. (I guess the pushing of frames from one VC to another saturate the PCIE bus?). it could be my VC being stressed from rendering 3840x1024 but UT2004 runs the same speed as Crysis warhead so it can't be my VC not having enough power
4) doesn't work with SLI. seems to use only one GPU
5) the color on the L and R screen is downsampled to 16 bit and the image seems to be alittle bit blurried
6) LAG . the L and R screen kinda lag behind the main screen by about 1/4 or 1/5 of a second.
softTH is not usable for fast paced FPS games but for non realtime games like RTS and RPG (mabye flight sim and racing but haven't tried it yet) it is amazing.
with that said, it still is an AWESOME piece of software and somewhat usable. once u tryied surround gaming.. it's hard to game in a single monitor