flow jet is what I have, used it for about 5 years, probably 30 times per year since I dump at home and need to go up a few feet to the sewer cleanout. So far very reliable.
The downside it is takes longer than using the slinky to dump and since stuff moves slower, flushing the black tank is IMHO a necessity.
Never had it clog or stall.
My advice is they are very good when you need to go uphill or a long way. but if you can reach with the standard slinky going flat or downhill, the slinky is a quicker solution.
I NEVER use it at a public dump station, or when hooked to sewer at a campground no need to.