PS, Perfect uninstaller is one I'll not try out. It will download free, scan an uninstall routine (or whatever you call it) for free, but will not actually uninstall anything until you pay for the program.
Once you've paid for it, if it turns out to be not what you really wanted, you have to try for a refund.
Up to you, but I wouldn't.
Trials of software I've used in the past that work in a more commercially open way might give you, say 3 or 5 or 7 actually full featured operations, so you can see the thing actually working, and feel the benefit. And then, when the number of trials are up, it stops working and you either pay or uninstall it.
That to me is a preferred trial software.