Question:

[reelapeelin]

Originally Posted by Destroyer

and the impeller is made of some kind of hard plastic.

I'd go w/a softer material over hard plastic any day...there is no give w/the harder material, so more prone to nick the edges as sand and other hard debris are pushed between the impeller tip and the housing...chinking away the edges will eventually lead to loss of pressure/volume...

In a perfect world where nothing foreign could get into the pump, maybe the harder material wins, but for real world use, the softer rubber's gonna offer better/longer performance.

On a global basis...I'll be willing to bet there are more (many more) rubber impellers out there in use than harder nylon...and that's because, I think, one word...reliability.