anyone have any experience of using the newest Drobo S (the one with five disk bays and esata) in comparison with the other small sized Drobo (the one with four disk bays, FW 800). I've read lots of reviews of it, but none that speak specifically to whether or not the overall architecture of the unit is improved in the newer model. The five-bay S model is considerably more expensive and i am trying to figure out if it is worth it.