Most of this is on Panasonic’s website.
But you cannot edit AVC-Intra natively in FCP at this time, it has to be transfered to ProRes. AVC-Intra50 is half the size of DVCProHD (and Intra100).
So if you want to edit nativity with mxf you need to stay with DVCProHD.
The benefit of editing natively is you save on transfer time. You can also save on HD space but I don’t recommend ever editing on the only copy of the footage.