Weeeeellllllll, I use a PC600 at the day job. Admittedly, I don't know all that much about it. We only use it for printing CYMK stuff and a as a second plotter. There never seems to be enough time to sit down and figure it out.
We use it mostly for the one off stuff. It's great for graphics on illuminated signs --- where there's some distance between the viewer and the print. There's great density to the colors that beats most inkjets hands down. If we're having a good day and press all the right buttons, it can be great for smaller informational signs --- at 100% density on the colors.
However, there is one issue that grinds on me when I get finnicky. It is a banding that happens as the cartridge prints from row to row. The tape overlaps itself as it prints. It's most noticeable in the tints. It's just a wee bit of a darker line where the tints overlap. Buuuuut, I could be too fussy. Spot colors at 100% probably won't show that.
Also, I think it goes through the cartridges fairly quick --- a 10% tint uses as much ribbon as a 100%. That's the drain. I don't write the check, but it sure seems pricey to run. It's also gone through 2 heads in 2 years --- buuuuut it does actually push through quite a bit of work.
Before you buy, definitely try to get some printed samples with the art you want to print --- Heck, pay a couple of bucks to go through a first run of decals if you need to. That might also give you a pretty good idea where you might need to be in figuring the costs of your decals (Well, unless the PC600 is priced cheap nowdays)
As stated earlier, keep it clean and dust free.
That's the best $.02 I can offer --- geez, I'm feeling a touch guilty about that, too --- can I send ya a nickel to make up for the post?
vid
And, I don't know all that much about plastics, but does over the counter vinyl stick to PET? ...in the environment you're putting it through?