I ran a Predator for 6~8 years on my old truck. It's a good carb for it's purpose, it's extremely throttle responsive and can take a fair amount of bouncing before it stumbles. Don't put it on anything you want decent mpg from, mileage will drop to able a 1/4 of what it was with a regular carb (my truck went from 12 to ~4 mpg).
The can be very vulnerable to dirty fuel, just the orange film left from gas will shut one down, literally. The upside is 30 minutes and a can of carb cleaner and your running again. They're extremely simple, only 2 moving parts in it.
They would have you believe you need a carb with the street idle circuit for use on anything other than a racer but mine was the race version and wasn't a problem to tune or adjust/set idle. I used it on my daily driver/wheeler for years.
Towards the end TARussell and I were using on his roller motor in my truck at local mud bogs. We thought it ran great and was doing a good job until someone offered us a Dominator to try - no comparison, Dominator wins. After comparing the 2 carbs, the Predator was real lazy getting to WOT whereas the Dominator was almost scarey it was so fast.
I'm not knocking the Predator, it's a neat carb but imo not for racing.