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I've had excellent performance and reliability from the Western Digital Passport Portable drives. Having used them since they were first introduced, I've not experienced one failure. I have six of them of various capacities 2 at home, 1 that I carry with my MacBook Pro, 1 that I carry with my ThinkPad T60 and two at the office.

While I've tried many other brands, the WD Passport has been the only drive that is very consistent in it's performance, only requires a USB cable to connect and power the drive, and runs very cool and silent. Plus they are usually the least expensive as they are so popular you can always find them on sale from a variety of online vendors.
 
I have a passport. I havent used it much but so far I really like it and the price was great.
 
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