two AC110s for sure. Then you can stager filter changes and have two filters that will last the life of the tank! They are very reliable and simple filters with lots of room for Bio media. IMO the only HOBs worth purchasing.
aqua clears are the only way to go if its a hob. i run them in all my tanks. id go two 110's or two 70's would work too. i like how it airates and filters. basically its a hob canister.
Well if the cost is an issue and the only choices are what you stated I would go with the two penguin 350s. They will do an adiquate job of filtering an average stocked 75g tank, plus you get the safety of two filters.