It wasn't intended to be an argument just a statement about how I feel about my filters. I happen to like the hang on tank filters. I like knowing the water will probably not be able to get out of the tank. The few canister filters I have seen with my own eyes have been under the tank with hoses running to and from the tank. I don't really trust anything that is external to the tank. I have a sump on my 90g with an overflow box, and it is the only source of stress to me. I am constantly checking to be sure the flow hasn't stopped and water isn't about to overflow. The canisters might filter marginally better but to me it is just not worth the added worry. I also like that my heater is in the filter and heats all the water evenly. Again, it all comes down to personal opinion.