Hi all, i need a new computer and thought about sharing my thoughts/dilemmas .. I'd appreciate your advice. Currently i have dell n5010 connected to Dell u2312 screen at home, i use my comupter for light coding, surfing and downloading, i'm not playing games on that computer.I'm mostly working it in house and i do want to possibilty to travel with it. I want to upgrade to a MB and this is where i have debates - I'm buying the computer at Hong Kong (possibly next week) - currently the options are 1. 13" MBA with upgrades CPU/RAM. 2. Refurbished 15" rMPB with 8/16gb ram, possibly GeForce instead of the integrated graphics *option 2, because of the added memoty and added GPU is much more expensive, i read that the HD4000 is having troubles with the Retina display, is it true? even when not playing gameS"? *As you read, currently the computer is connected mostly in house to an external display - but when i do leave home with it, are the differences between the retina and the air's display so much noticeable? *how is 13" screen comfortable for programming? do you find it comfortable? *what would you suggest me to get? thanks!