Eric over @ TweakHound has written a comparison between a few different XP-Tweaking tools.
He compared tools like X-Setup, NeoTweak, mi-Tweak XP and other, non freeware tools for their usability.

Since I put together my XP Tweaking Guide I've been asked to review several XP tweaking programs. I've also been asked by readers to recommend one of these programs. I'm going to look at several tweaking programs, some free and some not. Each program will have a very brief description (I'm not here to advertise for them!) and a screen shot. Conclusions and recommendations will come at the end. Read the comparison over here.