Java has one MAJOR flaw in windows, you can't keep it up to date automatically. The "Auto Update" feature just downloads new updates, and doesn't install them unless you click. Also when it does install a new version, it doesn't remove the old version. That wastes space and is no good. The software helps. Schedule it to run every day and it will keep your JRE running happy!
Running this program broke the Java plugin for Google Chrome because of how it removed previous versions. I would not advise this for Chrome users.
This appears to have stopped working as of version 7u51. It removes old versions, says "downloading" new version briefly, claims to install it, and exits. Otherwise, it's a great program when it worked.
This app is DANGEROUS for any developer because it will not only delete old versions of the runtime, but it will also delete ALL development kit versions of Java, as well as screwing up the Android SDK.