I started using SE (V5) & Pro E (2000i) at about the same time (1999). The company I was at had had SE about 2 years and was introducing Pro E, theory was it would allow us to work better with our customers but in practice it was because the new Tech Director had it at his last place and thought it was Gods gift. Plan was I'd mainly use Pro E and accordingly I got training on Pro E. As SE was being phased out I wasn't given formal training.
Pro E ended up costing our company thousands due to the impact it had on schedules. One significant projects cost more than doubled due to the extra time taken with Pro E V SE.
I spent days with PTC reps trying to get Pro E configured to do the things we needed it to do without much success.
I never got good on Pro E and nor did any of my more experienced colleagues.
I know how to use SE fairly well and at work am my groups SE expert, remember this without any formal training until a couple months back when I took advanced assy.
In fairness I know Pro E is meant to have taken leaps in usability since then and from an employment prospects point of view I wish I was better on Pro E but there you go.