I think I may have already posted but nit sure. I list my preferences as follows:
1 - CATIA - I worked as an airframe designer for a major defense contractor and CATIA rocks. Very powerful, but with a somewhat steep learning curve.
2 - Unigraphics - Also used Unigraphics a bit as the contractor I worked for used both CATIA ans UG. UG is also very powerful. Likewise a somewhat steep learning curve. More familiar with, so prefer CATIA.
3- SolidWorks - Much less steep learning curve. Can do most things you would ever need to do, but UG and CATIA are better if doing anything with complex surfaces.
As an aside, I was a beta tester for Ashlar Vellum way back when they were first incorporating solid modelling. Back then (1997 or 98) the program was not stable enough. I eventually abandoned my beta testing and have not picked it back up since. Even then it had some cool features and I am sure it is much more mature, after all, it was in beta when I was using it.