The Cipher Shield provides a reliable solution to lock down your external drive data against theft. We were very pleased with its performance. The encryption mechanism has no direct influence on the performance of the hard drive itself. Since there are very few 2.5" products on the market, the Cipher Shield had to compete against many 3.5" models, but it managed to hold its ground.
Since barely anyone will want to launch larger applications directly from an external hard drive, the access times play a minor role. And the transfer rates are restricted through the USB anyway.
We advise against using the version with 40 bit encryption, however, because 64 bit keys in today's PCs can be hacked in no time. Therefore, customers who are serious about security should purchase a device with 128 bit encryption. Unfortunately, the price is very steep: about $300 for a 40 GB hard drive is a lot - even with these features. And the price here only includes the 40 bit keys that we tested.