I actually bought 3 of these for the simple fact that it's so compact and it worked no worse than the other ones. At first. But after 2 of them broke (I got the 3rd one as a gift and it didn't last her for long either), I started to think that it may not be user error after all!
While its mini size is awesome (I like everything mini), it's also its downside: it's not as effective. Inevitably you are forced to squeeze harder and because it's plastic, it ends up breaking. I had high hopes for this product, but sadly it didn't last for very long, 2-3 months at the most. The rubber pad kept coming off, too, which made using it even more annoying. Not sure if I'll be able to get my money back (re: Sephora's lifetime guarantee referred to in the original post), but am definitely willing to try.