When PM was installed, there was some demographic transfer problem that ultimately meant I could only use PM appointment scheduler, and NOT the AC scheduler. Well, I happen to like the AC scheduler better, so their fix was to completely disable the PM scheduler. I was told alternately that it was either a bug or that AC's plan is to get rid of the AC scheduler in favor of PM, but I could continue like this for now.
I mention the above only in case the issue might apply to you and if it does, you have heard the explanation I was given.
Right now, PM support is such that, in my opinion, if you are considering PM, I would suggest you delay it.
