If you don't know how a program works then don't bash it.
For your concern, I have Revo installed in my computer and I use it. It's a great software. But it is not a panacea.
And definitively, avast uninstall tool does the better job.
Please, don't post here as the other are idiots.
I post about the software I use, test.
If you reboot when the program tells you to then it cannot remove the left overs.
I know how Revo works. But you does not seem to know how a program is programed to be removed after boot by itself (and Windows).
Notice how hhtmp88 thanked me first.
Proves how can bad advice make harm to not advanced users.