First of all, I get that the 11 can do everything, thats not whats being debated, this is like asking what is better: Pepsi or Coke? Its opinion and clearly the 3 of you have the 11", so you're hardly unbiased.
I have owned both 2010 models and now use the 11" every day. RIGHT NOW, The size makes sense for what I need it for, on my desk in class for note taking, etc. Smaller footprint over the 13 actually makes a big deal in a small space, the instant on/off and smaller size make it quick to put away and take out many times, which I need to do often.
That said, I would prefer the 13 if I didn't need to move as often and had more space when I did set up.
I own and use the 11 but prefer the 13. I provided the criteria I did based on my use of each model for 5 months each.