Which pump is better?

The Mag 3 has a head of 10'. They are recommended as the best water cooling pump because they have a really high flow rate with a high amount of head = good performance. Also, for the price, you can not buy a pump that offers the same performance. As NoAffin stated, they do have problems with leaks (not always). As many people have discovered, when using a Mag 3 NOT submerged, they may leak a little. This is an easy fix however, just a little RTV Silicone Sealant around the impeller housing. However, I believe that Danner has addressed this issue and newer models do not leak as much. I am using the Mag 5 model, have had zero leaks whatsever, and it is a DEMON OF A PUMP! It puts out major flow!!! Almost too much, I constantly have little air bubbles in my system because the flow is too high and the water gets very turbulent in my resevoir. It doesnt' affect temps so I am not concerned about it.