Comparing only the 13" models, you get 2 Thunderbolt ports so you can use an external display and Thunderbolt Ethernet adapter at the same time. Actually if you

Comparing only the 13" models, you get 2 Thunderbolt ports so you can use an external display and Thunderbolt Ethernet adapter at the same time. Actually if you use HDMI for your display you can use a Thunderbolt drive as well. The 13" Retina is only .5 lbs heavier than the 13" Air. It still has integrated video but it's a generation better than the current Air's.