I'm not certain about patrol but the main strengths of OEM as I see them are:
You've already paid for it.
Three tier architecture makes deployment very simple and secure.
Very powerful notification tools.
Security is very easy to configure with different level administrator roles.
Events, jobs and alerts are all very easy to configure.
The only real downsides of OEM are:
The initial installation can be challenging (I regret to say, I had to loose all my techie credibility and read the manual ).
Java based client may run slowly if your desktop P.C's are poorly specced.
I've looked at a couple of other tools (Embarcadero and Quest) and neither offered any functionality beyond what OEM gives you. You may prefer the interface though.