You asking me 4wd ? I use mine their fine .What do you do with the batteries from older versions?
I can see certainly why one would keep an Inspire and the like for doing pro work and use the Mavic for fun, but I don't see why one would retain a P3 or P4 if you also have a Mavic since the capabilities are so similar. How many can you fly at once? I think I'd get the money out of the older hardware while I still could.