I have found, in 737, that F30 seems to be easier to control in a gusty crosswind than F40.
On a side note this brings up a question that I've always wondered about and I have received 2 different answers from different people ( so maybe pprune isn't the best place to ask!!) but here it goes. When you're extremely light, ie. positioning an empty aircraft, what's your preferred landing flap? And why? (Assuming runway length, weather, wind etc. isn't a factor)