I use a Danner mag 5. I would have bought the mag 3 but when I saw the price difference was only like $6 for an additional 150gph I said what the hell and got the mag 5.
I would say that for the money they are quite good. The only thing that can be annoying is a slight clattering noise that comes from the magnet riding on the shaft. Danner gave the magnet some free rotation so potential pump jamming material could pass through, which isn't a problem for watercooling applications. I should glue the magnet and shaft together but I'm too lazy.
