I just picked up one of these drives, as I already own the My Passport Essential 500GB unit. It's such a nice little portable drive that I had to buy the Firewire 800 version for my Mac. Much to my surprise, the Studio is significantly larger than the Essential version. In fact the thickness is about 20% greater, and the other two dimensions are slightly larger as well. It's not a huge deal, but I was quite surprised. Anyone know why it's larger? Is it just to make room for the firewire components?