
Here is the picture of its back. It has power button, 2 firewires, 1 eSATA, and 1 USB. I am using eSATA for the best performance btw. WD included firewire and usb cables, but didn't include eSATA cable. I had to spend additional $15 to buy eSATA cable.
The performance is very good. I did not benchmark it but I have experiences using several external hard drives. I find this unit is among the fastest ones. Technically, eSATA is a lot faster than firewire. I noticed its eSATA is not much faster than firewire. I timed how long it takes to copy 3GB video file. The result was almost the same. eSATA was only a few seconds faster. I also times how long it takes to back my PC and I did not noticed much difference between the two. I am a bit disappointed that WD did not designed it to take much advange to eSATA.

My other favorite feature is auto on/off. If you leave the cable connected to the PC, it will turn itself on when you turn on the PC. It will also turn itself off automatically when you turn off the PC. Therefore, you never have to get up from chair to press the power button. Good news for lazy people like me.
After months of use, I discovered there are a few annoyances. One is its utility software. It comes with ultility software that allows your diagnose, format, and switch mode between Raid-0 and 1. The problem with this ultility software is not fully compatible with Vista. Under Vista, you won't be able to switch mode. My Book Studio comes with default setting of Raid-0 (Stripe). I want Raid-1 (Mirror) for safety. Fortunately, my PC has dual boot with XP. I booted into XP and switched the mode to Raid-1.
The other thing I don't like is after 15 minutes or so of idling, it goes into sleep mode. Under sleep mode, the hard drives stop spinning to save electricity. From sleep state, it takes about 7 to 10 seconds for it to become active again. It is no big deal for most people. Most would use it for backup and would not access it frequently. But I access it very often. Frequent 7 to 10 second waiting annoys me sometime.
I bet many of you have some concerns with noises from PC. Well, I do. When I build my PC, I always do every thing to make it as quite as possible. I just can't stand having jet taking off in my room constantly. When I bought My Book Studei Edtion II 2TB, I was worried that it would not be so quiet because it has 2 hard drives. After I turned it on for the first time, I was very surprised how quite it is. It is not 100% silent. There is still audible noise from hard drives. It is, however, quiet enough that does not disturb me at all.
Overall, this is very well balanced external hard drive. Fast, reliable, and reasonably priced. It is great for backups or video editing. I highly recommended it. Just make sure that you don't buy Maxtor. I never had good experience with that brand.Pro:
-Very Fast
-Good quality
-5-year warranty
-Quiet
Con:
-No eSATA cable included
-Lack of full Vista support
-A bit slow on waking up from sleep mode
-eSATA is not much faster than firewire