Personally, I prefer to uninstall Mac apps simply by dragging them into the trash (strangely, this is actually one of my favorite parts of Mac OS X). However, on the off-occasion that I need to get rid of any extra files left behind, AppCleaner does the trick. There's no hassle to it, and the process is almost completely hands-free. Click twice, and you're done. AppCleaner doesn't have any extra features, but I don't need anything else anyways.