I just got mine, so I can't speak to the durability or usage.

I wanted to correct something said by a few of the other reviewers: this (at least the black one) does, in fact, have two slots for cards (perhaps they changed the design recently).  You can see it in the picture as there's one slot with the clear plastic window, and one staggered slightly above that.

Other than that--- I can't  believe I spent $18 on this dinky little thing, but I love it so far and would buy it again.  Seems very durable.