If you (1) are willing to pay a bit more and (2) can do with the 4GB RAM limit, and (3) can work with an external monitor when you need it, get the most expensi

If you (1) are willing to pay a bit more and (2) can do with the 4GB RAM limit, and (3) can work with an external monitor when you need it, get the most expensive MBA 13" base model with an upgraded processor. If not, get the 3rd 15" MBP and upgrade the processor, screen to hi-res and HD to SSD. I just bought both recently.