OWC’s Mercury On-The-Go FireWire 800/400 + USB 2.0 is a Mac-ready, fast, bus-powered portable hard drive that eschews style for substance. Equipped with USB, FireWire 800, and FireWire 400 connection capabilities, the Mercury On-The-Go is a versatile drive that is easily portable.

The clear plastic casing allows you to view the hard drive mechanism on one side and the metallic cooling unit on the other. Since the drive is bus-powered, an AC adapter isn’t necessary. A couple LED activity lights are a nice touch, but this drive isn’t exactly a fashion accessory.

OWC doesn’t bother with superficial aesthetics, instead focusing on performance and customization. OWC’s Mercury On-the-Go line is bit different than many drive families we’ve reviewed. Customization is standard practice, and when you order from OWC, you can specify the type of connections, bus speed, and the capacity. We tested a 7,200 rpm, 320GB portable external drive with FireWire 800, 400, and USB 2.0 connections. This covers most of the bases in terms of connectivity, with a good spectrum of versatility (the absence of eSATA notwithstanding) for an external drive.

The Mercury On-the-Go weighs only 11 ounces and is slightly longer and bulkier than competing external drives. OWC says you can fit the drive in your shirt pocket, but you’d have to have a really big shirt with really big pockets.

The drive finished our 1GB file copy test in 35 seconds using FireWire 800, a result that was among the fastest external drives we’ve tested. The 1GB duplication test results were equally impressive; these times are similar to G-Technology’s G-Drive mini ( ), our current top performer. The OWC drive actually bests the G-Drive mini’s time in our Low-Memory Photoshop test by a few seconds, outside our margin of error. If you need to use the drive via a USB connection, its scores compete with several USB-only external drives we’ve tested.

At $180 and $.56 per gigabyte the 320GB On-The-Go drive is a bit pricier than competing drives on a price-per-gigabyte scale.

Macworld’s buying advice

The Mercury On-The-Go FireWire 800/400 + USB 2.0 is a fast Mac-ready portable drive equipped with versatile connection options. It’s also competitively priced and matches up well in all departments against competing externals. Unless you buy your storage solutions based on appearance, you’ll be quite satisfied with this drive.