for that price if your in the market for a canister.... I would say its worth the gamble ! look at the GPH ! noise never bothers me really I enjoy the humming.
Those are decent filters. They are so cheap because it's a pond pressure filter. You need to use it with an external/submersible pump, it doesn't have and internal one. Yes the work for an aquarium.
In my experiences less money equals bad quality. So if its cheap its probably a piece of crap. As far as the flow rate it depends on what your tank theme is. For most tanks I go with 5-10 turn over per hour. so 1000gph would be fine for a 140