In the long run, over-filtrate, it will be to your and your fishes advantage. I suggest if you're going to run a canister filter, run a hang on back filter that provides a waterfall as well.
I use only the H.O.B. style filters myself (Aquaclear), and not canister style. I tend to get the filter that is recommended for my size tank, and buy two and run both together. If one should fail, I have a back up. You can also clean one filter one week, and the other the next week maintaining a healthy amount of beneficial bacteria in the filters. Plus, I would rather over filtrate than under filtrate.
I highly recommend the AquaClear filters if you decide to go with a HOB filter. For a canister style filter, Fluval Fx5, I've never heard anything but good about these.