I like the ACs but don't think the 110s are big enough. I'd go with 2 500s.
I like the action of the Emp 400 but don't like to use pre-packed cartridges.
Carbon that's packaged in a plastic bag or cardboard boxes is probably already used up before you get the cartridges.
Also, with the ACs, they'll continue to work even if the water level drops a few inches. Making them suitable for a turtle tank or something you don't fill to the top. Emp 400s don't work very well when the water is down. At least, that's my experience.