Maintenance apps

has any one used this appliaction?
http://www.apple.com/downloads/macosx/system_disk_utilities/maintenance.html

or use similar applications that they would recomend?

A lot of people here will recommend a similar program called Onyx. It has a ton of features, but is also easy to use.

Another utility that some people recommend is MainMenu. It does pretty much the same thing as Onyx, so it's really just a matter of preference.