MRC 6100 is a reeflo hammerhead design with a better seal and 5 year warranty. Looking at getting on to teplace my hammerhead so I can replace the seal on it and put it in storage.As discussed above, I have never had a ReeFlo get to two years without leaking, having bearing problems and even had one literally catch on fire. There are more efficient ways to get water up a level from a return pump, but if larger flow pumps are on your mind, then AmpMaster has been great for decades. I have not used the MRC pumps. Hammerhead is a lot of watts to do this job, IMO... like any of these kind of pumps.