I bought a Hypertherm unit, and, have been happy with it, although like most Posters here I use cutoff wheels-more and more I find myself using my 4 1/2" Milwaukee with a cutoff wheel for the thin stuff.
If I have to cut out a lot of metal, then I will break out the Plasma, or when I am cutting thick stuff over 16 Gauge-it's just faster, and the clean-up (for me) is about the same, cut-off wheels vs. Plasma.
My Brother-In-Law has started a company where he makes replacement power seat adjusters for Cars where you can't buy them separately, (where you have to buy the complete adjuster assemblies from the Dealer-Dodge Pickups, Mustangs and the like), and he has been using a cut-off for this for about 2 Years or so-he came to visit and I let him try my Plasma-he fell in love (as his cuts are of the 1/8"+ variety, and it has saved him a lot of time.
Would I buy one again or recommend one? Like Ogre suggested, unless you are doing more than one Car, or are doing a tremendous amount of customizing or chopping, I think you can "get by" with a variety of cut-off wheels-would I sell mine? Not on your life!