G-tech Gsafe drives
I've had a 500gb G-Tech GSafe since they were first available last spring. I can't speak for the 1 terabyte model, but the 500gb has two 500gb drives that mirror each other automatically. I really like the idea of having two backups whenever I'm working and I don't have to save my work to two separate drives. I would assume the 1 tb model to be the same. When I was making the decision to purchase one, I found the G-Tech folks at tech support helpful--you should be able to go to the G-Tech web site and send them an e-mail and ask them if the 1 tb is really two separate drives.
FWIW: My GSafe has been running every day since June and I've had no problems. It's very quiet and using the firewire 800 with my Mac, very fast. I have all my commercial photo work since June stored on the GSafe and even though I'm nearing capacity, it's still running smoothly. I keep the Gsafe on my desk next to my computer and at the end of every day, I back up any new work to a regular G-tech 500g hard drive which I keep locked in a safe. That way, if someone breaks into my studio and takes my GSafe, I'll still have everything backed up.
I'm planning to purchase the 1 tb model early next year to replace my 500 gb drive. Good luck with your decision.