So I just started college, and realized that my 4 year old 13" Aluminum Macbook is running slow now. As much as I love it, it is time to upgrade. I'm not sure why, but I am drawn more to the 11" air over the 13", although the 13" provides more options. Has anybody had issues using an 11" air coming from a 13" screen? Also, what do you think about using the air as a main machine? Anyways, thanks!