I don't really understand this point - I live in Vancouver, so I fly United for most of my US-bound flights. (AC wants me to go through their YYZ hub - Flip that.)

From a pure seating perspective, E+ is way better than anything in AC's Y class. On UA I can actually work on my laptop in E+. Can't do that anywhere on AC.

What exactly are we 'giving' Mileage Plus members on AC? There's no E+ on AC's domestic flights...