[JROM]

Someone in this thread said that Cad was unrelated to the Cam.
You could not be more wrong! The person who designs a part may not have any idea what information is needed to make the part. A 3D model is not always the geo. you need to make the part. So a good programer needs to know how to extract the features from whatever file he is given. For most parts a 2D wire frame is all you need. Also when cutting surface files you may need to extend or trim surfaces to get the result your looking for at the machine. A good Cam programer MUST also be a good CAD driver. And a good Cad package is a primary feature of a good CAM system.
Another guy said that you tend to favor the system you know the best. I think that is very true. I once was working for a new startup company that wanted to make high end pistons for racing motors. I was tasked with researching software for design and manufacturing. I looked at about a dozen defferent packages and combinations of packages. I won't tell you what I picked in the end but I will tell you that looking back it turned out that I had chosen the same software that a majorty of people were starting to move toward. I'll give you a hint. Now a days if you can't work with solids your screwed big time. Everyone is designing in solids and if you can't work with them you have excluded your self from about 85% of the market. Almost every software company has adopted the Parasolid kernal into there software and the ones that didn't are falling by the wayside.