I have used many of them ranging from Unigraphics, Mastercam, Catia, Smartcam, Pro E etc..... so far
Unigraphics seems to be the best all around package
for NC Programming. Unigraphics also sends you a
postprocessing module with your software, some of the
others you will be required to go to a third party.
Also, with Unigraphics you would get all of the solid and
surface modeling, assemblies, drafting in one bundle, usually the "manufacturing bundle" goes for about $25,000, with maintenance being about $400/month---- with your maintenence you also get excellent phone Technical support that is also not always available with the others.
Hope this helps.