Any idea on the pro/con of the various "Hard shell" sleeve cases? I'm just about to pull the trigger and I don't want to drop my 3K investment and shatter the glass. I'm looking for a hard shell sleeve but I'm concerned about the added weight and bulk. Hard Candy Bubble sleeve? Booq viper sleeve? Thule? Any comment on these cases? In my mind I would be able to use my macbook while in the sleeve for quickly browsing or quick notes. And also easily take it out for long term work..