I am a graduate school in psychology and want a lightweight (relative to my current MB) laptop that will not mimic a jet engine when it encounters flash, has decent battery life (not the 1hr im down to now), and can run windows seamlessly. Would I notice a substantial performance gain with just a Macbook Air or is the rMBP a sensible investment? I will primarily use the computer for internet, word processing, data analysis and web application development. I will be commuting with the laptop by bike, but didn't notice too much of a weight difference at the Apple store. I will be using an education award to purchase the laptop so cost is not a major factor.