I've had my MBA 11 for about 4+ months now, and I've got a ZaggSkin installed to protect from scratches/dings and give it a customized feel. Now I want a hard sleeve to protect it while its in my backpack or luggage from being hit by other things or from falls. I'm not concerned about thinness, as it will likely stay in my bag all the time... Any suggestions? I've been looking at the booq viper, and the be.ez robe allure, but I wanna weigh any other options before choosing. Thanks!