I have used CCleaner with some decent results.

Anything I should know about it?

Not much, it installs and runs in the background. You can open it up and you can scan your browsers and can also scan your registry for errors as well. I also like Spybot too, more of a malware scanner but does help clear out stuff.

Wise Care 365 seems to work well for me. Has Disk Defrag, Registry Defrag, file cleaning, and trace removal. There are some premium features you can purchase, but most of the base level optimizations can be done with the free version. It even comes with a boot-up timer to see how long it took to start your computer :3

Just google "Wise Care 365" and look for a link from wisecleaner.com