[wattson12]

I have a 2012 13" air (i7, 8gb ram) at home and I use a 15" pro (2.3i7, 16g ram) for work. The screen on the pro is amazing, as is the speed (as you'd expect given those specs). I use a cinema display at the office but can work just as well on the laptop screen (my work is coding, so Xcode most of the day) and haven't found anything that caused the pro to struggle (I've not noticed any UI lag either).

That said, I still love (and probably slightly prefer) the air because its so small and light (ergonomically i prefer a 13" laptop), and the difference in power for most tasks is not that big (though its definitely noticeable when using Xcode on the air). If you took them both away and told me to get one, I'd get the air again.