PL: The Samsung S1 Mini is certainly small, we were shocked when we got it out of the box at just how small it really is. However the price you pay for having a 120GB drive the size of a pack of playing cards is that it is expensive. At £130 it's over twice the price of a 500GB 2.5-inch drive pricing a 500GB (they don't make them yet) around the £540 marker. That's around 10 times the price of a 500GB 2.5-inch drive at the moment.
So it comes down to whether you really need a largish storage solution (i.e., 120GB) in such a small package. I mean it's not as if you are going to be carrying this in your jeans pocket when you head out on a date (or maybe you are).
The S1 Mini offers good on performance and size, but let down against the slightly larger competition when it comes to affordability.