I agree on the "Pro" being subjective.

Pro is whatever a professional uses. Whether that's MS Paint, or Photoshop. Poser or Poser Pro.
Doesn't matter. :) It's whatever works.

My other half is a professional cameraman. He knows his stuff, and even he says that a lot of the DV Cams on the general (home user) market are good enough to be used in serious work.
The only difference is usually the kind of lens being used, but he said there are some non specialized cameras on the market which are better than a lot of the ones used for Broadcasting.
(Bear in mind that these guys pay megabucks for cameras (and lenses) though. I'm not talking about something that costs $1000.)
Thing is though, when a company like the BBC buys cameras, they won't be replaced inside of a year, like so many home DV Cams. So while technology moves on, the camera used to film a newsstory may well be 5 years old (or older, if it's not digital) and something a lot cheaper on todays market may well be far more sophisticated.
So don't let the "Pro" mislead you.

A Pro can get a hell of a lot out of your regular Poser app, while a novice will still struggle to produce something even close to it in Poser Pro.
If you know your tools, you'll produce professional results. I think the Pro version is simply tool for more advanced users who want more out of Poser than they get with the regular one, while it's still possible for a novice to get started in it.

It's what you do with it, that counts. :)

Silke