If you do decide to get a FP5 then I advise you use the SD card as “portable” or “external” storage, and not format it for use as extension of internal memory, since this option is well-known to cause problems. See the forum SD card guide.
As portable memory, you can still have apps like the camera, save directly to the SD card. Typically the only serious drawback with this option, to my mind, is that the SD card content won’t be encrypted automatically by the phone.