I agree with everyones post here.
I have bought 3 fluval 404's - all brand new. Used them for about 3 months and they started to leak, every one of them. They are crappy filters, will never buy one again.
On my 5 fresh water tanks, I run Eheim all the way. I find that the 2028 model is the best and easiest to use.
As for my saltwater tank and my reef tank, I use a sump, with foam and bio-balls and skimmer on my 90 gallon tank and a AquaC Remora skimmer on my 50 gallon reef tank. I tried once putting a canister filter on one of the salt water tanks and I think because of the salt content int he water, the filter foamed and bubbled some and lost the vacume pressure. Filter kept stopping, but it worked fine on my fresh water tank.
I believe in AquaC series skimmers for the saltwater tanks and Eheim for the freshwater.