You know, a lot of people buy this noname crap and wonder why it pukes on them. They use the lowest quality parts they can get their hands on, and whatever drive manufacturer will give them the best deal and throw it together.
It pretty much comes down to you get what you pay for.
I myself traded an enclosure from someone just for the hell of it. It was a noname deal. I put a good drive in it. It failed on me within the period of a couple of months. Not the drive, the controller in the cabinet.
It happens all the time, then people come in here crying the blues, asking why it doesn't work. That's why.
There are two solutions. The first one, the one I ended up with, was just putting a large drive in my computer, and then having a fileserver. Obviously the fileserver isn't practical for most people, but for those that can do it, it's highly recommended.
The other is to get a brandname external. Maxtor makes a phenomenal Maxstore unit that is very reliable. You pay a little more, but it's worth it.