I've had a fluval, but got a lemon(LOL) The head leaked and caused me to take down my whole tank because I thought it was leaking. Nevertheless, they seem pretty good and I just think I got screwed by some old stock. My favorite so far has been the magnum 350 and the H.O.T magnum. The magnum 350 like Jeff said, can get noisey when starting up (as air gets trapped) or if you get some loose pieces of charoal in there, but once the water completely fills the cannister after starting up and the air is pushed out, they are pretty quite...Atleast all of mine were (had 3) Also, you have the ability to run a polishing cartridge in it which is great after a water change or aquascaping. After 24hrs of continuous use, I've had polishing cartridges completely stop flow! It removes that much, but not recommended for use longer than 24 hs at a time. Just make sure you keep away from the sponges or sleeves. They are bad new IMO as they will trap junk from the tank and it will definately breakdown in there and deplete water quality before you change it out or clean it. With cannisters, pulling them apart is a task in themselves and people usually just neglect them because of the. The quickest and easiest one to use is the H.O.T mangnum IMO. HTH