Believe it is made by Hatachi, probably before WD bought them. Reviews I have read are mixed with about 50% saying excellent and 50% saying horrible. Not much middle ground. I would appreciate any hearing about experience you folks have with this HD. Thanks.I would not use an Hitachi drive in an external case.  Buy either a passport Western Digital or a case USING an SSD if you want say 128gb of storage that you can CART around. For larger amounts of data consider a powered desktop hard drive like the Western Digital mybooks.    Lisa_maree is being very conservative. 
Most venders will offer some kind of warranty. If a drive is defective or weak, it shows up in the first days  of use and testing.  You can use a diagnostic utility to test the drive. Western Digital has a free utility for generic drive testing and will catch the most COMMON drive problems.

On of the concerns about external drive enclosures is ventilation and heat dissipation.Aluminum is better that plastic. Also, PAY attention the power supply. Some can barely run the drive motor. Most vendors offer some kin of exchange if you find an enclosure that is POORLY made.