For all around use, I would get the 24", as I believe that the longer barrel would work better for hunting.
I have multiple barrels, and had been using the 18" for the last couple of years. Swings very fast, and I only had issues on some targets where the shot spread from the cylinder bore would not allow me to get the steel down most of the time (split popper, where you are to only down one side). This year I am switching to a 26" barrel with chokes to try that out, but just in practice I can feel the difference in moving from target to target. If this does not work out I will save up to buy a 21" and keep the 26 for hunting. :D I do like the shorter barrel, alot.