So, what's the best sleeve for a 15" rMPB? After reading this thread, it seems like Booq Mamba sleeve is the best one available and Incase (including the slim one) are not tight enough. Is it still true? It it worth spending $40 on Booq compared to about $15 on Incase (eBay)? Also, those of you who've had Booq Mamba for a while, does the zipper really scratch corners?