Hi, I am a new user and just finished my conversion of a Sieg X3 mill to cnc. I have chosen Dolphin CAD as my interface to Mach3. and so far no problem (only me, ha) The support is outstanding and I think that is all you need to get going. As I am in New Zealand and a bit removed from everything (time zones) is great to see such a quick response from Dolphin.
Would be happy to recommend this CAD system and a great team up with Mach3.
Hope this will help some people to make up their minds when it comes to choosing an CAD/CAM system for hobbiest.