I like having a canister and a HOB filter. I don't use carbon in the canister so it doesn't need to be replaced and I don't need to open the canister for months at a time. I use carbon in the HOB which is easy to replace. Its also good to have a backup filter. Once after cleaning, I managed to put the canister back in the tank stand in such a way I kinked the hose and stopped flow. It was the next day before I noticed but at least the HOB was running.