CandyBar has more options (quite honestly, I've forgotten what they are though, because it's been a long time since I last tried CB – I usually use ShapeShifter for changing my icons).
ThemePark makes themes; ShapeShifter applies themes (so, TP is for developers, SS is for users).
APE is a system framework thingie that allows you to install a lot of different hacks (such as, as you know, ShapeShifter). APE is basically what powers Haxies.
ShapeShifter will only cause a minor slowdown when launching apps (since that's when it's "telling" the application to look for GUI resources elsewhere), but it's very minor (less than a second), and it doesn't affect performance at all while you're using the application, just launching. I don't know about other Haxies, although I know ClearDock won't such up any power either.
ThemePark makes themes; ShapeShifter applies themes (so, TP is for developers, SS is for users).
APE is a system framework thingie that allows you to install a lot of different hacks (such as, as you know, ShapeShifter). APE is basically what powers Haxies.
ShapeShifter will only cause a minor slowdown when launching apps (since that's when it's "telling" the application to look for GUI resources elsewhere), but it's very minor (less than a second), and it doesn't affect performance at all while you're using the application, just launching. I don't know about other Haxies, although I know ClearDock won't such up any power either.