I have had this CnMemory external hard drive for around a year now. Unfortunately I bought it not because I thought it would be safer to back my files and data up in case my laptop crashed, but because my laptop already HAD crashed and I had experienced first hand the pain of losing all that music, the photos, and everything else!
I paid around 50 pounds for this hard drive, as I remember, which was at the cheaper end of the scale for a 1000 GB machine. I would say the unit is about 12 x 22 cm and about 2 cm thick. Thus it really isn't a big unit. However, in comparison to the more portable units available it does seem rather clunky. It's definitely not something that I would want to be carrying around often, so if that's important to you give this model a miss.
In terms of operation, this really couldn't have been any easier. It comes with a USB connection and power cable. Just plug both in and you're off. I didn't even have to format this because the guy at the shop did it for me. It didn't look difficult though, so don't worry about that.
Then, at least using a Mac as I do, it's just a matter of dragging and dropping everything you want onto the hard drive. I just go into the Music section of my system in the "finder" folder, for example, and drag the whole lot over. This way everything retains it's original tagging and folders etc, and it means that when I want to update my back ups a few months down the track, I just delete the whole folder from my portable hard drive and replace it with the current folder on my laptop. That way I don't have to worry about trying to remember which music is new and which is old etc, and it doesn't matter that I don't have TIme Capsule or a similar program. The same goes for Photos, and the "Documents" folder on your computer.
I haven't had any laptop crashes since I bought this hard drive, so I haven't (thankfully) had to test it out under pressure, but I do occasionally delete photos from my laptop or films etc to free up some space, and it's then easy enough to pull stuff out from the hard drive and copy it over to my laptop again. On a Mac (and I assume on a PC too) this is just a matter of dragging and dropping the relevant files onto your desktop or into a folder on your laptop.
Therefore I do feel like this is a trustworthy hard drive, although I will say that it sometimes makes some rather odd noises when it's loading up, which do make me a bit nervous. Normally machinery like this makes a humming noise if it's working hard or booting up, but this hard drive sometimes makes a clunking sound, which I admit does freak me out a bit.
I think that generally this is a good and easy to use hard drive, and I've never had any problems with it. However, I would seriously consider buying a smaller, compacter, more transportable one at this stage, unless you're very sure you will only be using it at home.