The multiple accounts one works FAIRLY well...it's not perfect.
And the way the interface is setup, seemingly in an attempt to make absolutely SURE that you have to check or uncheck about a million checkboxes isn't the greatest. My first thought was that Nick was a bit 'happy' when he coded the interface for that...lol
It does work though. Sometimes, as with many parts of cpanel, there will be an error and it won't tell you why, or will claim success when the action actually failed, but if you use Cpanel I'm sure you're used to all that.