I am launching a new library on SharePoint. All subscribers have asked that a reporting feature is added to quantify the volume of readers and who the readers are.

From an internet trawl I found the "Report Centre" feature where auditing at the site collection level needs to be switched on by the administrator.

What are teh implications of switching this feature on for a (500 Site) Site Collection. In specific reference to space taken up by this feature and it's visibility. We only need the reporting option for one site.