I formatted all my backup external drives using ExFat format for a Mac running 10.7.3 and a PC running Windows 7 64-bit.
I am using WD, Samsung Spinpoint, and Hitachi bare drives in BlackX SATA hard drive docking enclosures and I transfer the bare drives using WiebeTech DriveBox Anti-Static Drive Case for 3.5" drives to an offsite location.
So far the ExFat drives have allowed me to move data from both laptops to the drives. Is this a wise move or are there any unforseen dangers using ExFat formatted drives with both systems?
Guy at computer store said bad to use ExFat and I should just format each drive for Mac and PC. I am mainly storing photographic images and videos ranging from 20mb-500mb in file size.
I see no problem with that. ExFAT just has a bad reputation because it's not used by many people. It works tho.
I suspect "guy" is a PC or Mac only guy and therefore thinks they should keep their respective formats - very old fashioned way of thinking.
You should be fine. If you wanted to use something else, you could use FAT32, but that's a bit old, and if your drives are over 130GB (or somewhere close to that number), you can't use it. And if your videos ever exceed 1GB, again, FAT32 isn't good.
Really though, you should be fine. If you're reusing/recycling the drives regularly, just make sure to do full formats every once in a while (if a weekly cycle, do it every 3mo or so).
The only thing I would highlight is the fact that you're using HDDs for off-site backups. Drop one drive once, and that drive is toast (so is your backup). Tape is much much safer (albeit more expensive).
1. consider configuring a NAS offsite and pushing your backups over the wire.
2. consider using a cloud backup (given the sizes in your OP, I'd suggest Livewire or Carbonite - the give unlimited capacity, but Carbonite does start to throttle your uploads; once at 300GB and again after 500GB. @the 500GB throttle I'm getting about 900MB-1GB of upload/day.)