I played with two portable models, one from Asus and the other from Lite-On. The two are similarly slim and square in design, and housed in a silver chassis. And some of their specs are similar, too: 8X single-layer write-once DVDR, 2.4X double-layer DVDR, and 24X CD-R/RW.
The $130 Asus SDRW-0806T-D boasts faster specs than the $105 Lite-On SLW-831SX, however, for its DVD+RW writes (8X versus 4X) and DVD-RW writes (6X versus 4X). Unlike its internal and full-size external siblings, this drive ships with packet-writing software--the software that enables you to drag-and-drop files onto a rewritable disc. (For Asus's other models, if you want to use packet writing, you'll need to go to the Nero Web site and use the OEM license code that comes with your Asus installation discs to download and reinstall a version of Nero that has its packet-writing component.) Lite-On includes the necessary software (Nero's InCD) on its installation disc as well.
If these specs seem slower than you're used to hearing with respect to DVD burners, that's because they are. Since these drives both use the same slim design as drives installed in notebook PCs, their specs and performance are more akin to what you'd get from a notebook burner than from a full-size desktop-PC burner. Desktop-drive specs are at least 16X for write-once DVD and 8X for double-layer DVD writes, for example--a dramatic difference from the Asus and Lite-On models' 8X write-once single-layer speed and 2.4X double-layer speed. For example, in the PC World Test Center's performance tests, the Asus took 2581 seconds to write 7.9GB to a DVD+R DL disc, and 673 seconds to write 4.35GB to a DVD+R; the Lite-On model took 2720 seconds and 824 seconds on those same tests. In contrast, Plextor's PX-760A completed the tests in 850 seconds and 351 seconds, respectively.
The Asus drive has another edge in its inclusion of both USB 2.0 and FireWire interfaces. The Lite-On model offers only USB 2.0.
However, the Lite-On has one trait that sets it apart: It uses a slot-loading mechanism, which remains fairly unusual among PC drives (see Plextor's PX-716AL internal drive for one example; for such a drive installed in a system, see Apple's Mac Mini and MacBook). The slot-loading mechanism adds an extra layer of coolness to this svelte drive, and it eliminates the need to have a clear, wire-free space for a drive tray door to pop open; it operated smoothly when I tried it.
But while it looks great, a slot-loading mechanism carries two potential risks. For one, if you use disc formats that don't conform to the Orange Book and Red Book standards (which govern the parameters that optical drives operate within), you could have difficulties using your discs; for example, a Dual-Disc music CD and movie DVD, which is slightly thicker than what the standard CD and DVD spec calls for, could have problems loading in a slot-loading drive. Also, if you use the drive with a disc that has an adhesive label, that label could get caught in the mechanism if it's not applied evenly or properly. (I recommend against using adhesive labels if you can avoid them; read one of my past columns for more on disc labeling and disc longevity.)