Some of the contributions here made me laugh out louder than I should have in the library
...
Kidding aside (I'm honestly serious, OP), since none of these processors will disappoint you in terms of power, you might want to shift your focus on battery life instead. I had a 2011 MBA that was advertised with 5 hours of battery life at the time. From the beginning on I barely ever got 3 hours. I took it back to Apple manifold times, but in all their system tests the battery turned out to be fine. We clean-installed the OS multiple times to make sure nothing was secretly eating battery life in the background... no avail.
Long story short, one genius pointed out that the short battery life was due to me having upgraded the processor to an 1.8 GHz i7, whereas the battery tests that provided the numbers for the Apple ads were run on the base model's i5 processor, which - at least at the time - consumed much much less power.
I don't know if any of this still plays a factor in today's processor-battery-relationships (I'd like to think they harmonize a lot better now), but I surely stuck to an i5 core on my new rMBP for this very reason.
Kidding aside (I'm honestly serious, OP), since none of these processors will disappoint you in terms of power, you might want to shift your focus on battery life instead. I had a 2011 MBA that was advertised with 5 hours of battery life at the time. From the beginning on I barely ever got 3 hours. I took it back to Apple manifold times, but in all their system tests the battery turned out to be fine. We clean-installed the OS multiple times to make sure nothing was secretly eating battery life in the background... no avail.
Long story short, one genius pointed out that the short battery life was due to me having upgraded the processor to an 1.8 GHz i7, whereas the battery tests that provided the numbers for the Apple ads were run on the base model's i5 processor, which - at least at the time - consumed much much less power.
I don't know if any of this still plays a factor in today's processor-battery-relationships (I'd like to think they harmonize a lot better now), but I surely stuck to an i5 core on my new rMBP for this very reason.