The lowest maintence and ease of use in my opinion are the Fluval systems.Cleaning the media and canister is very simple.Part replacement is not that difficult.
Personally I like Fluvals. I really don't understand all the fuss about priming. Usually when you attach the tubes it primes itself. Just wait a few moments, plug it back in, and BAM you're done.
i am with dirty fish on this one i cant see where every one fussing about with the fluvals. my first filter was a eheim i also own filstar and two fluval 304 & 404. i have more trouble with my eheim if i completly drain the hose. i am thinking about buying a filstar outlet and put on my eheim just unscrew the cap and pour full of water. the newer eheim might be a lot easier i just dont know much about the newer ones sinces mine is an older model. i think they all do an excellent job of filtering. i guess the reason i kept buying the fluval i was well pleased with there performance and most of all they were not as pricie as the eheim. i think all the fluval bashing is just like in nascar between ford and chevrolet both of them win races. you might have one that will win just a few more but they all compete well. i am planning on buying a 300 gal. tank from glass cages and i want to try the via aqua 750 planning to all so use a sump with this tank.
Id say Ehiem's are the best but the flow rates are a little low If you get an ehiem i would suggest going for a bigger canister then is rated for your tank. For example the smallest ehiem is the 2213 rated for 60g tank i believe. The flow was really slow even on my 20g but that is the concept behind ehiems filters. the slower the water passes thru the filter media the better it get filtered. thats why i always go bigger...got to have some water movement!