I always used them and i'm very happy with the results. Water is always clean, and they are easy to work on. I know pp don't like the noice but mine are pretty quiet for the most part. I run 3 emperor 400's on my 125g, penguin 350+150 on my 55g, and a penguin 350 on my 30g. I was going to get a fx5 for the 125g but im glad i didn't because of the cost. I saved $150 buy using the 3 emperors. One day i will switch to canister filters because i hear of all the great results, but for now im happy.