Buy the Gariz leather half case. A case improves grip and the Gariz has a metal base with a very neat rectangular machined hole which aligns perfectly with the access door for the battery and memory card so that you can leave the case screwed on via a gunsling (supplied) screw into the tripod socket.
You never need to remove the case to change battery or card, whereas the Fuji grip accessory needs to be removed each time you need access to battery or card.
The metal base is also machined for a conventional tripod socket set centrally therefore enabling use of the camera within the Gariz case for tripod work and still providing access to battery and card.
IMHO the perfect case and the FP1 with case fitted, still fits into my Billingham Small Hadley bag together with lens attached plus two other FX lenses, spare battery, card case and flashgun.