When I started with Intellinet, I realized quickly that I needed some external storage as my laptop's piddly little 60Gb drive was rapidly filled with virtual machines. So I went to NewEgg to do some shopping. While I was looking, I kept coming back to the eSATA enclosure and SATA drives. the drives are faster and with the eSATA ports I could triple my throughput to the drive. This is important when copying multi-gigabyte virtual machines around. So I picked up a 2.5" SATA drive, a SATA/USB enclosure, and a PCMCIA card to give me a pair of eSATA ports.
How's the performance? Let's let the graphs speak for themselves.
my SATA drive hooked up to my system via the eSATA port:
my SATA drive hooked up to my laptop via USB 2.0:
my internal IDE harddrive:
The gist of the graphs is that the eSATA connection is on average 67% faster when transferring data and bursts up to 3 times as fast. This sure makes VMs seem responsive.
I've also got some anecdotal evidence. Sebastian at Intellinet was transferring 200 Gb worth of files from his laptop to his external drives. This took 6 hours on the USB 2.0 connected drive and only 1.5 hours on the eSATA connected drive. Of course, he was using a 3.5" model but he has the same brand enclosure and PCMCIA card.
These pretty graphs are courtesy of the HD Tune disk benchmark utility - http://www.hdtune.com/