Thank you for all of the responses to my original post. After researching it a little bit more on my own, I realized that some of the sellers on ebay were mixing up their terminology and that was part of the reason why I was confused.
The biggest issue I still have after looking into this further is that even though the theoretical data transfer maximums of 480Mb/60MB/sec. with a USB 2.0 external case should be more than sufficient for cd-rw's using the 33.3MB/sec. standard, it doesn't appear that all of the external cases can handle sustained data transfers at those levels.
I found reviews of the Atech Digilog ME-320 on Burnoutpc.com and extremeoverclocking.com and while the reviewers were impressed by the unit, one said that it only got to about half of the theroretical speed transfer levels when testing a hard drive and the other said its performance lagged a bit. Maybe this would be different for a cd-rw and maybe sustained data transfer levels are not relevant when it only takes about two and a half minutes to burn a cd-r with a 52X24X52 drive. I don't know as I'm pretty new to all of this. This model is certainly the most affordable one out there and is the one that you can find a ton of people selling on ebay.
I've been deciding between this Atech Digilog model, a generic CompUSA aluminum case version, the ADS Technologies USBX-804 and the newer Belkin F5U209. I'm leaning towards the ADS version as I've read a number of positive comments on it (including some from this forum) and it is the only one that provides a rating on sustained data transfer levels - at 35MB/sec., which should guarantee great performance with a cd-rw.
I would be interested in the Belkin as well, but it was only released a few months ago and information and detailed specifications on it are hard to find on the internet. The Atech Digilog model can be had for $46 at Computergeeks.com, while the Belkin and ADS models are going for $100 at my local Compusa and are probably available cheaper online. The aluminum Compusa generic goes for $69.99.
I'm probably making too much of this, I'm sure that all of them will probably work fine for my purposes. I will probably end up going with the ADS model. However, if anyone has any experience using any of the other models, I'd appreciate hearing any comments.
Thank you and Happy New Year.