We have three GY-HM700U cams used in both studio and field production. Two have the Fujinon Th17X5BRMU lenses. Cam settings are 1280X720 at 60p HQ. We use Toshiba, Sandisk, Transcend and iData 16GB cards without any troubles. We've been physically taking the cams directly to our Macs to transfer files as it seems if you pop the cards and put them in a card reader it's necessary to reformat the cards when you put them back in the cam. (You can't pick up where you left off like a cassette. Are we doing something wrong?)
In both applications they make beautiful pix and are thoroughly reliable except for the "dead pixel" syndrome which is a known problem. (It happens on the cam which came off the first JVC production line a few years ago.)
We recently took delivery of a GY-HM100U and haven't thoroughly used it yet. I loused up the first field shoot as I inadvertently kept triggering several buttons as I cradled, held and moved the cam around.