Just to be sure everyone is on the same page, it is the chipset in the
external enclosure that determines whether or not large drive size is supported and that is completely independent of whether or not large
internal drives are supported.
That does not explain why the 500GB WD drive is recognized as 128GB on a Mac and 68GB
in Windows 98. I can only speculate it is because of improper/incompatible jumper settings (I am assuming an ATA drive) or because of the proprietary chipset in the Maxtor enclosure only working properly with a Maxtor drive.
I have not heard or seen any negative comments about the Acomdata enclosure. Personally I have had excellent results with Other World Computing's
Mercury Elite and
Mercury Classic enclosures.