I am undecided between macbook air 13inch base model and MBP 13inch base model. Portability is important, but my main concern is performance on bootcamp/window7 for work. can anyone chip in your thoughts how the 13inch air fares against MBP 13inch? Will it perform as well as other PC ultrabooks? I will be doing web surfing, entertainment, etc. on os x and work related on PC, so my usage will be 50/50. Any thoughts?