I went through this as well and went with the 180 because: A) 24" is plenty high for fish to swim. They swim side-to-side, not up & down. B) Much easier maintenance. You'll probably have to get on a ladder to reach the bottom of a 220. Also the water changes are less. And fir me, because I bought the Marineland 180 RR tank, I also bought their high end Monterey stand, and it holds both the 220 & 180. I wanted a stand that was capable of more weight than I had. Also that 6 extra inches on the 220 can make or break your lighting for corals.
If you looking into the Marineland tanks, I would definitely suggest looking at the Monterey stands. Much better built, nicer, and has removable side panels. Also has a hardwood top with cutouts for the corner overflows and the tank sits down in it so you don't see the bottom plastic around the tank at all. There are 3 doors on the cabinet. 2 open and I can easily fit a Trigger Systems 39 sump straight in without angling it first. The 3rd door is only 11 inches wide. I didn't want to go with their standard stand with that much weight, condensation, evaporation, ect...