I'm currently using a mba 13", but after looking at my friends' rmbp's screen, i start debating whether to upgrade to rmbp. My major concern are: 1. the weight it feels when you hold it with one hand in open mode and move it around the house. does it feel considerable heavy if hold it in such position despite the advertized half pound weight? As I move it around a lot around my apt. 2. Does it feel comfortable if i use it a lot on my knees and put the edge of the trackpad against my belly? Will the sharp edge cut my bell? Any input is appreciated!