I try to avoid software that has its own website like that. You have to remember that these people have to pay their bills somehow, so there has to be a catch. Glary makes money by trying to install the ASK.COM junk on your computer (make sure you uncheck those boxes during the install) but other than that is unobtrusive from what I can tell.
With that being said, I just installed slimcomputer just for the heck of it, and I have to say, it's kind of nice. It doesn't really do anything that you can't do from Windows, but it does put it all on one neat spot. It also gives you the option of a USB stick installation, and doesn't try to install a bunch of junk at the same time.
For me, the usefulness isn't really anything to brag about (like I said it doesn't really add much of anything) but it does make everything easier to get to, so I can see how a less knowledgeable user could find it to be quite handy. It also does a scan for unnecessary software and all it found on mine was ATI Tray Tools and my Logitech Profiler software (both of which I want to keep by the way).
I'll give it.... 4 out of 5 skuzzies... mostly because it seems honest and straightforward.
I just hope they don't start adding more crap to it that skuzzy wouldn't like if they become popular.