I know there have been similar discussions before, but I have a specific question I'm hoping someone can answer. Whenever people complain about the 13" rMBP being underpowered they seem to be comparing it to the 15" pro. What about compared to an air? My last computer was a maxed out 2011 11" air. I never noticed any slow down and was very happy with its performance. Is the 13" rMBP going to run noticeably slower than that?