I think the biggest thing with pumps is what are you using them for? I've got a few different types and they are all good in their own ways. What application do you plan on using it for? Return, if so how high of a head? Skimmer running? What size tank?
Personally, I like the Blueline pumps for pressure pumps (used for running a venturee skimmer & high pressure nozzles) and the sequence (reeflo) pumps for return/water movement, but I run a rio 2100 on my 65 gallon upstairs, and for the $35 I spent on it I am still impressed. For in tank water movement you cannot beat the propeller pumps, MJ mods, koralias.... gotta love lots of movement for low $s!
I have heard a lot of good things about giant pumps, but I have heard a lot of complaints about them getting hot or seizing up too... I have never owned one though, so I don't know if any of that is just because so many people have them or if there is something behind it.