It also depends on what targets you wanted to concentrate on. If you want to do widefield shots mainly...nebs, large galaxies, many globs etc, you're going to need plenty of chip real estate and short focal lengths (which will mean a reducer in the optics), so the Atik383L+ is your best bet there. However, most targets will fit comfortably in the FoV of the 314L+ (most PN's and galaxies) and will do alright with the larger targets at native FL. But with the reducer, you'll do better for the larger targets as the FoV will increase.
Grab yourself this...
CCDCalc, find the specs for the cameras you're looking at and then stick the specs into the program and see what you get.