That's a tough choice as both are great handguns. I would vote to keep the compact though because it can serve dual purposes. It could be used in a pinch in it's compact form as a backup for the Shield if it was ever necessary, and equipped with full size magazines, it's almost like having the full size handgun
It's just much more versatile. I doubt that the extra 1/2" barrel length on the full size makes much of a difference as far as accuracy, but the slightly smaller size of the compact will make a difference if you ever have to carry it concealed temporarily.