The Good: The compact WD My Passport Slim drive offers fast performance, comes in a metal casing, and is comparatively affordable. The Bad: The drive could stand to be a little slimmer, especially the 2TB version. The Bottom Line: The speedy My Passport Slim is an excellent mobile backup and storage expansion option. Its rugged, metal-casing design is a great extra, considering its affordable cost. The My Passport Slim is the next step up from WD's previous My Passport Ultra portable drive, which came out in March. The new external storage device is slightly thinner, and comes in a metal enclosure. It also offers all the goodies found in the previous model, inlcuding WD SmartWare Pro data protection software, up to 2TB of storage space, and very good performance. Most importantly, the Slim is more affordable, with a suggested retail price of just $100 for 1TB, the same as that of the 500GB Ultra at launch. The 2TB version of the Slim will cost just $150 when it's available later this year. You can expect the street pricing of the drive to be even lower.If you already have a USB 3.0 portable drive, there's no need to upgrade, but if you're looking for one, the My Passport Slim will make a great storage device for travelers looking to carry lots of data in a limited space, or perform backups on the go. In all, I recommend it. For more great portable storage device options, check out these alternatives. \t \t\tDrive type \t\t2.5-inch external USB hard drive \t \t \t\tConnector options \t\tUSB 3.0, USB 2.0 \t \t \t\tAvailable capacities \t\t1GB, 2TB \t \t \t\tCapacity of test unit \t\t1TB \t \t \t\tDimensions (LWH) \t\t4.33 inches by 3.14 inches by 0.48 inch (1TB) or 0.7 inch (2TB) \t \t \t\tWeight \t\t5.6 ounces (1TB) \t \t \t\tOSes supported \t\tWindows 2000 or later, Mac OS 10.4 or later \t \t \t\tSoftware included \t\tWD SmartWare Pro, WD Utility, WD Security \t \t Design and features Measuring 4.33 inches by 3.14 inches by 0.48 inches, the new 1TB My Passport Slim isn't exactly slim. In fact, it's just .02 inch thinner than the previous model of the same capacity and is about exactly the same size as the Toshiba Connect. And at 0.7 inch thick the 2TB version of the new drive is not slim at all. However, the new drive has an aluminum casing, instead of plastic, and feels very sturdy in the hand. The design is two-tone, with shiny white on top and the rest of the body painted in dark blue. It's one of the best-looking in WD's My Passport family of portable storage devices.Like most USB 3.0 portable drives, the My Passport Slim has a Micro-USB 3.0 port on one side and comes with a short standard USB 3.0 cable. This is the only cable you need; it handles both power and data functions. Designed to work best with USB 3.0, the drive also works with USB 2.0 and in my tests it had no problem drawing power from any USB ports. The drive also comes with a small user-guide booklet and a nice traveling pouch.Out of the box, the Slim is preformatted for Windows (NTFS) and works immediately when you plug it into a computer. On a Mac you read data from it but can't write to it until you reformat the drive into HFS+ or exFAT. You can do this using the Disk Utility built in to Mac OS X or use the WD Drive Utilities software preloaded on the drive itself. In addition to WD Drive Utilities (Windows and Mac), the Slim comes with the WD SmartWare backup program (Windows-only), as well as WD Security (Windows and Mac).