3rd party Xbox 360 Hard Drives?

I recently did some searching to try and find a decent priced HDD upgrade and I noticed there were some 250 GB ones popping up on Amazon, Buy and other websites for under $60. I double checked the details and noticed that they were 3rd party manufactured.

Do these work just as well as the real ones or does Microsoft block them from working through weekly Xbox Live updates and/or bannings? I really want an upgrade from my 20 GB but don’t want to risk wasting money with getting ripped off by microsoft or getting ripped off by a 3rd party company. :arazz: