Keith, I think the wording did not make a meaning I intended.
English is my second language as you know.
What I have meant is that VATSIM and PE have different purposes, VATSIM is oriented to provide ATC coverage for the whole world with the best professional service they can offer but they lack in the frequency management obviously.
CTAF or UNICOM is to my understanding, very important part of voice interaction in flight and tuning to proper frequencies is another major part of above.
PE has frequency management set up exactly like in real life.
As far as controller skills, VATSIM has great controller in general but since the new ones need to get their skills on VATSIM, that is were the skills will vary.
I have never said that VATSIM controllers are unprofessional..
To make the story short, in my opinion, VATSIM is oriented more to be a universal tool for ATC interaction while PE is the one to use when one wants to learn proper ATC interaction in US.
Yes, it is only in California but rules will apply to all US.
I hope that explain a bit better what I had in mind talking about VATSIM versus PE.
Cheers, AJ