Systweak

About six years ago, I bought a licence for Advanced Systems Optimizer (ASO) from Systweak, after finding a reference to them online, and after reading their literature or a review (can't remember what happened a day or two ago even :), I decided to try it.
After using it for a while, although it appeared to do a reasonable job, I couldn't be sure it wasn't smoke and mirrors, and when their application for picking up potential spy cookies, etc., only took a few seconds to run and finish, as compared to other dedicated spyware taking ages to do the same thing, I didn't bother to renew.
A couple of years ago, I decided to try a newer and much more sophisticated version, and now regard it as my best ever buy. It has taken the place of lots of other maintenance software and does a better job - much better in some cases - than the dedicated software to clean the registry, find spyware, look for outdated drivers (and automatically download and install the new ones), defrag the system, etc., etc.
Put it this way, one of my friends and my wife's uncle, now have licenses for it, and both are extremely impressed and pleased they took my advice to get it. My wife's geeky family with Windows machines have ignored my recommendation: but then that's because I'm not a geek and I'm not as computer savvy as them. I think they assume I'm just too easily impressed. Anyway, apart from very specialized software, I'd never switch to any other maintenance software again.