Demon carbs

I'm looking at a Demon carb. Mighty Demon
850. Its used and I don't usually buy used
but it was only used about 5 times for testing an engine. Don't know anything about Demon
Carbs. I can get it for about half the price of new. Any thoughts on this
I had two of them 10 years ago both of them were junk.
One stuck the throttle shaft the other I never could get to idle.
I know that Summit stopped selling them because of all the returns.
May be a different story now.
I have seen a number of parts being sold as "test only", buyer be ware.