I have been using the MC Prime since 1.0 and I was using earlier versions of MC since long before PTC bought it.
I don't use Creo and I don't use much of the higher end capabilities of MC (either Prime or <15) so I may not be representative of the larger user population.
I am generally writing simple systems of algebraic equations but I find MC's ability to keep track of the units of measure extremely useful and a great way to avoid unit errors. I find MC to be a great way to document calculations and methods... Something that Excel doesn't, ahem, excel at.
The Prime upgrade seems to have been, in many ways, rather cosmetic. The GUI now looks much more modern and the MC page now "looks" very much like a real laboratory notebook (blue grid line background and all). But even I noticed some MC 14/15 functionality that was missing from the early Prime version (e.g. the ability to define global definitions). Pretty much everything I missed from MC14 is now available in MC Prime 3.0 but I gather from other people's posts that some of the more advanced capabilities in MC 14 are still missing in Prime. I did download MC Prime 3.1 but found that the new features were all about CREO (whatever that is ).
I do get the impression that MC is the poor sister of PTC's product line and does not get a lot of development resources given the somewhat meager improvements in each new version.
