Hob filters can add aeration if the water level is lowered (waterfall effect) I'd only recommend aqua clear or marine land's emporer models.I prefer the ac myself for hob- better filter sponge and you can easily make it a reugium for some cheato and pods if you want a mandarin fish.( under the tank reugiums don't work well for this because pods get chopped up in the pump going into the tank ) canisters can be a bit more to clean at first but I don't think so once you do it a couple times, they usually run slower and have more media space(better contact with filtering materials) also the water return is in the water so you don't get bubbles in the water like you can if the water level drops when using a hob filter. Canisters are quieter and you don't need space behind the tank for em. Generally you want a minimum of 2x the amount the filter is rated for on your tank with hob filters (filter rated for 100g max on a 50gallon tank) and you can use a canister rated for what it's worth.( 50 gallon max on a 50 gallon tank) most run two filters in case one goes bad and you can clean one real good without worrying about losing all your bio bacteria because you have the other filter still going. Clean them alternately so you don't lose all bio bacteria at once. In my 55 gallon tanks that are heavy bio loads I use one AC 110 and one Marineland Bio Wheel giving me approx 750 gallon per hour turnover which is around 14x turnover a hour. You won't need that much with a low bio load and or better circulation.
