I run a Cascade 700 and Cascade 500 on my 50 gallon, and I like them. They're not discussed much on here, as they have taken some heat for bypass problems. I don't think it's much of an issue, personally. I have 4 of these canisters, and I haven't had a problem with any of them. Just my $0.02, I'm sure others will recommend eheim, rena, etc.