Nope for me sketchup is the greatest of them all on my opinion, I mean you can integrate anything out of anything, engine parts, gun parts, houses, buildings, entire city, I can copy anything by only using sketchup, 2,3,4 axis CAM works, so yes if you are too familiar with it you dont need any preset programs whatsoever, sketchup is the only program I used on all our CNC works on the 3 types of machines. Im not really saying that sketchup is too simple, Id rather say it`s too complex for a free 3D program, complex = custom, custom means you can do whatever you like and can think of.