if your building one car, don't. if your a fabricator that makes everything, think about it. i have access to one and never use it. i also bought a torch and sold it a few yrs ago. i prefer using a cutoff wheel in a small grinder. it usually takes as long to clean up a plasma cut as it would to cut it with a grinder.
plasma cuts new stuff a lot better than old rusty stuff. can't cut anything with oil or paint on it. $700 would be a lot better spent on a portaband.
i do a lot of fabricating my tool of choice is a cutoff blade followed by a bandsaw for production cutting.