There are two very nice features that make KCleaner its own brand of disk cleaner. The first is the option for secure deletion. KCleaner lets you choose from either regular deletion, 1 pass, or 3 pass deletion, and then deletes all junk files in that way.
The other unique feature of KCleaner is "automatic" mode. When you do this, KCleaner will automatically clean every certain number of hours, meaning that you don't ever have to worry about cleaning again (as long as you have the settings how you want them). KCleaner can also minimize to the tray, and also start with Windows, so it can keep your computer clean with little to no user interface.
But it also can be very hands-on. It shows every listed file, and you can check/uncheck individual files that you don't want to be deleted. It actually seems to pick up more than CCleaner, since it just now found 700mb that are dispensible, whereas CCleaner found 200mb (but that may have to do with the options). KCleaner is about 1.7mb in size, 2mb RAM on idle, 5mb on scanning/cleaning.
On top of all this, KCleaner is portable, just click the 7-zip/Zip icon on the KC Softwares download page. I have to say, I love CCleaner and Piriform, but KCleaner looks like it might split my heart when it comes to disk cleaning. (Forgive me, CCleaner!)