Finely tuned capability restrictions may be defined for users and programs. Some environments, though, need security features that go beyondwhat MPE's built-in functionality can offer. Fortunately, these needs can be addressed. We've been discussing certain security aspects here, specifically for the HP 3000. The problem is we don't know much about it, including price.
Price is a big issue, too.
It uses logon UDC, and this is a bit of a problem because incoming FTP users can bypass it. We bought it so long ago that I am not sure of the price, but I think it was in the expensive end of the market. My understanding is that Private is not being significantly enhanced any longer. Also, Private will age passwords as a function of time, but I'm not aware that it can age by number of logons per user. If I'm incorrect, I ask forgiveness.