I started wtith PE1, and upgraded to PE2 when it came out.
I've been working with it almost a year now, and it seems like I've just scratched the surface of what all can be done with it. I've worked on my own, along with getting several books that have really helped, noteably Richard's and "50 Fast Digital Photo Techniques", along with "Photoshop Restoration and Retouching."
I never had
PS, but from what I've read in magazines and forums, the results (unless you are do very serious work for magazines or other large-scale publication) seem to be the same. In fact, some things in PE (like photomerge) I have heard do not exist in
PS (probably in the next version?). With what was in PE, along with Richard's disk and book, I feel that I can accomplish most anything that I want to do with photos. Maybe in 4-5 years I'll want more (though I doubt it).