I was very unhappy with the Speck case.

The static they generate fiercely attracts abrasive dust: mine badly scratched my brand-new MacBook within a week, although everything was scrupulously cleaned before installing. (Directions warn of this, advise removing and cleaning the inside surface of the cover often.) And I'm much more compulsive than most about setting it on clean surfaces, keeping laptop case immaculate, cleaning hands before use, etc.

Mac store I purchased it from took it back without complaint after seeing the damage.

Now happily using the zipperless neoprene Case Logic foldover, have only been asked to remove the laptop once. (Argued; won.) But the deep scratches still bug me.