If you first take a look at the benchmark numbers, the DataFab drives cannot keep up with the Western Digital solution. On the other hand, the Western Digital is a loser in terms of mobility; the MD2 drives being smaller, lighter and easier to open, making them more convenient if you want to want to switch between different hard drives.
Many of you may dislike the 2.5" drives because of the mediocre performance. The objection is basically justified, but at the same time, I cannot see much sense in using a heavy desktop drive that is shock-sensitive and not designed to be portable. Additionally, the 3.5" drive would only be faster in theory, as it would be slowed down both by the USB interface and also the Firewire controller used in the MD2-FW1 - just like the 2.5" Fujitsu drive we used. A faster controller chip could certainly be used, but what for? Users who want high performance probably won't go for a FireWire or USB solution, opting for a SCSI system instead.
The MD2 drives are an attractive option for users who require portable data, but without high-performance ambitions. The Firewire version seems to be a good choice for people who both use Windows PCs and Macs: DataFab provides all the necessary drivers for both.