A few issues I want to talk about -
1. Is the uninstaller in Windows enough? 3rd party uninstallers just call the same entry point to uninstall anyway, all they do is have a nicer GUI and maybe list more stuff.
2. Uninstallers that work by diffing - i.e. taking a snapshot before and after install, then comparing. Are these reliable? There's too much going on in the OS, and no way to determine what's related to the app you're installing, or is just additional filesystem/registry activity.
3. Does Windows even support true uninstalling? I say not. Because every single program that has a trial version leaves behind remnants, so you can't install it again and restart the trial. And many programs never uninstall properly. e.g. crap like Acronis TrueImage, and leave behind tons of stuff.