I can't find many reviews of the two drives and wonder what their drawbacks and assets are. I personally don't care about size of the drive and just want something that I can use in the long run. It looks like the Pegasus has hard drive bays, which suggests that it can be user serviced or upgraded with better drives in the future. Of course it's twice the price, but also for twice the amount of storage. If you've seen any good reviews or own a Pegasus, please post.