According to Microsoft the Surface Pro 3 weighs 800 grams which is about 1.76 pounds. The type cover 2 weighs .55 pounds. So it's about the same weight as the 11.8" MBA (2.38 pounds) and lighter than the 13" Air (2.96 pounds). Also according to Ars Technica the battery life is 9 hours. That's the same as the 11.8" Air and less than the 13"Air (12 hours). Considering the Air has what I would consider a real keyboard and trackpad I'll take the slightly heavier weight.
Only 9 hours?
Whatever will the people using the SP3 do?!
You do have a point about the trackpad, though. I'm using a first generation type cover, and that's my one complaint. The keyboard itself is really good, though.