XRF buyers guide

[Master Nater]

I'm on the fence about putting the $$$ into an XRF scanner and think this would be a great thread to have available for potential investors into these devices. They offer a considerable wealth of information that is necessary for the up-and-coming refiner, but on the flip-side, they are a considerable investment, for a hobbyist or even beginning entrepreneur. Can some of you who have experience with these tell us what you have, what you have experience with, what is worth the $$$ simply for refining, and what is not worth the investment? Are hand-helds worth the portability for lab work? Are desktop models as accurate?