The keyboard... I miss the chiclets. But it's lighter & smaller, TouchID is amazing, despite being a "downgrade" in model it's substantially faster for the things I do (raw photo editing, photoshop, web coding). Truetone is great, I don't feel a need for flux anymore. Also fewer bugs with iCloud - I could never get my airpods to show up in the sound menu on my mbp 13 but they work perfectly on the mba.