I just purchased this 500gb hard drive recently, and so far so good. I prefer having these external drives just incase I need to reformat the computer at any time. Future Shop had this on sale, because I'm pretty sure these devices are quite costly usually. It comes with a USB cord so you can plug it into your computer.
This hard drive allows you to have lots of space if you're a media junkie like myself. Lots of data, videos, mp3s etc. can be stored. It works great so far for me. The only thing though is that it is a bit noisy if you have it sitting on a desk. I am not too familiar with comstar products so I think this one I will give a go, unless something better comes along.
There is also a one year warranty on it, so I will see how this storage device works for me.