I haven't use SDS for punch/plasma programming, but I have used it for plasma and laser. It is not the best program available out there. The windows version is very difficult to program, the the dos verision was easlier. The nesting capabilties is limited.
You should check out Measurement Masters P.E.P.; it's expensive but an excellant program. The service center I worked for ungraded to a punch\plasma compiler after I had left the company. Previously used smartcam on a whitney plasma/punch.