My model Air for example is a 2014 13" base model. Would it perform everyday simple tasks as good as the Air or is the processor difference noticeable?
I personally haven't noticed anything on the rMB being slower than on my base model 11" early 2013 MBA. Granted the rMB has 4x the SSD space and 2x the RAM.
To be clear, the rMB experiences retina lag like the other retina laptops. I don't remember seeing UI lag on the 11" MBA but I could be wrong.
My model Air for example is a 2014 13" base model. Would it perform everyday simple tasks as good as the Air or is the processor difference noticeable?
I guess it depends on what you think are "everyday simple tasks" but in my experience with the rMB, rMBP and a 2015 11" MBA, yes, in "normal," "simple" everyday tasks there is no difference. I will say that I always turn of transparency to reduce retina UI lag, which an MBA obviously can't have.