SLIDESHOW (4)
		Slideshow | All Shots

The Studio Edition II looks exactly like the Mirror Edition, except that it has a silver-painted exterior instead of glossy black. It has the same dimensions and the same dot- and dash-shaped cutouts on three sides for ventilation. The dots and dashes are Morse code and apparently spell out words the WD marketing team wants you to associate with the products, like "personal," "reliable," "innovative," "simple," and "design." To a non-cryptologist, it simply looks like a neat design statement. On the back, instead of the Mirror Edition's single USB port, the Studio Edition II has all of the relevant external I/O interfaces: mini USB, FireWire 800 (compatible with FireWire 400), and eSATA. These are all the interfaces you could wish for in an external drive right now.

Within its case, the Studio Edition II has the same pair of Green Power 1TB hard drives as the Mirror Edition, and as with that product, the user can replace one of the Studio Edition II's drives if it fails. The Mirror Edition ships formatted for FAT32 with RAID 1 enabled, emphasizing its role as protector of your data. The Studio Edition II comes formatted for HFS+ (Mac format) and with RAID 0—which emphasizes speed and capacity over protection. This means that the Studio Edition II is a 2TB-capacity drive (over the Mirror's 1TB) and can fully support the faster FireWire 800 and eSATA interfaces. You'll probably need a third-party eSATA card on your as well as an eSATA cable (the drive's package lacks one). However, creative users will welcome the larger capacity (which you can get on the Mirror by reformatting the drive), as well as the speedier interfaces (which you can't get on the Mirror). I would categorize the Studio Edition II as abundant, speedily accessible, extra drive space to store your work on, rather than a device for safeguarding your backups (which is the Mirror's mission out of the box).

You can reformat the Studio Edition II as FAT32 or NTFS, but it comes formatted as HFS+ for use on Mac OS X systems. Likewise, once you install the WD Drive Manager utility on your Mac or PC, you can reset the RAID array from RAID 0 (striping, 2TB) to RAID 1 (mirroring, 1TB) like on the Mirror Edition. However, considering the Studio Edition II's speedier interfaces, why would you want to?

Since the Studio Edition II is so Mac-oriented (down to the silvery color scheme), I tested the drive on my MacBook Pro test bed, . However, the Studio Edition II is still speedy, taking only 49 seconds to copy our 1.2GB test folder using the USB interface. FireWire was even faster: 38 seconds for FireWire 400 (using the included FW400 to FW800 adapter), and 32 seconds using the FireWire 800 interface. By comparison, the Mirror Edition took a relatively leisurely 57 seconds to copy the same folder. These are a bunch faster than the RAID 0 formatted FW800, 44 seconds; FW400, 1:02 seconds; USB 2.0, 55 seconds. If you need speed and capacity on a Mac or MacBook Pro, the Studio Edition II is now the drive to get.

Like the Mirror drive, the Studio Edition II is marketed as a "green" device by virtue of its internal WD Green hard drives. While I was using the drive on my MacBook Pro test bed, the Studio Edition II indeed powered down to sleep mode quickly when it wasn't in use and also used very little power while active (under 20 watts). (The CMS dual drive we tested in 2007 idles at over 31W, while single-mechanism drives run about 10W.) The drives are RoHS compliant, and are marketed to be paired with Energy Star–rated desktops. Hard drives aren't part of the EPEAT initiative, so it can't get marks for that, but I certainly can count it as one of the products PCMag recommends as being energy efficient; and since it can replace multiple external drives by itself, it also gets good marks for space and material efficiency. The Studio Edition II therefore gets our GreenTech Approved seal.

The Studio Edition II comes with the same software package as the Mirror Edition: the aforementioned WD RAID Manager, WD Anywhere Backup, and trail versions of Memeo AutoSync and MioNet. As before, I consider the latter two crapware, but at least on Macs running OS 10.5 (Leopard), you don't need to use any of the packed-in software. You can use Time Machine with the Studio Edition II if you're using it as a backup drive. Note that the LED capacity indicator on the front of the drive displays usage only if you install WD RAID Manager, but the drive will still connect to your Mac or PC and work without the software.

Think of the Western Digital My Book Studio Edition II as the Mac-oriented version of the My Book Mirror Edition drive, but with more interfaces. If you need the speed of eSATA or FireWire on your PC or Mac, then go with the Studio Edition II. It's larger and more robust than the sealed La Cie Little Big Disk Quadra, and it's more advanced than the CMS Velocity2 dual-drive arrays that I've reviewed in the past. If you just need a secure, protected place to store your backups, then get the (slightly) cheaper Mirror Edition. Otherwise, if I were a businessperson or serious hobbyist, both WD drives would float to the top of my buy list.