I was under the impression some time back that overall cost of ownership of PRO/E was not all that much different than the overall cost of Solidworks (actual cost, not the other intangible costs).
I'm sure there are several consultants in this group that have both packages and can at least give some general numbers or differences in the percentages.
I'm under the opinion, if you don't do work for other clients and you don't share much or any data outside your company, and you don't feel like paying maintenance, then don't. I dealt with a hyd cylinder mfr who stayed at release 18 or 19 when we were at 2001 because they didn't see the need to change. They could still send out pro/e models and they rarely if ever needed to bring any in, so it worked for them.