They are easier to clean. I posted a thread yesterday I did a 30% change and after I filled it back up I noticed white worms all over the glass. I thought it was planaria, but wasn't sure. John confirmed that it was. I do anywhere from 30 to 50% daily and one 90% weekly. I have a canister on what was an old established 55 display tank. I am getting a 100 gal running soon and needed to free up another 55 for a grow out ( buying too many discus lol). Anyways, I was using the canister until I cycled the sponge filter. I only did maintenance on it once a week. This I feel was the source that fueled the planaria, because all of the BH that was getting pulled in there sitting for a week. Just pulled the canister today actually. Sponge's are a lot more convenient and don't suck up all that food causing water issues. If you do use a canister you may want to use a prefilter on the intake. I have done that before and I believe it was Pat who suggested it on my thread too. Once you cut back all those feedings canisters are good like a display tank for example. HTH