I'm awaiting delivery on a rMBP and have a 1TB Seagate FreeAgent Desk external HD that's always been used with Windows XP. How easy or difficult will it be to use with my MBP without losing any data? Ideally I'd like to both read and write of/to the drive. Edit: if it's any help I also have a Buffalo HD somewhere that I've never used. I can't remember the model though.