Full user review
"Use only for reference"
SO I only use it for reference and then go the specific sites to see if I need to download an update or if I already have.
As some said before: TechTracker also reports updates when you're already up-to-date, fails to catch some updates, and repeatedly tries to get you to upgrade software to versions that are either incompatible with your OS X version or require a paid license.
about what you'd expect for free...