So, I keep a MBA next to my LazyBoy (aptly named) for quick research on IMDB, etc. I keep an SP3 in my briefcase for work and travel. Some observations: The MBA wakes from sleep instantly when the cover is opened. The SP3 never does. I have to tap the power button. The MBA power supply turns green when the battery is charged. The SP3 does not. I would love to see this feature on future power supplies. The MBA battery will last, in sleep mode, for days. The SP3? Maybe 1/2 a day. The MBA screen brightness setting does not seem to effect the battery life. For the SP3, maybe a little. The MBA is perfect for lap surfing. The SP3, not so much. The MBA has multiple USB ports and a nice trackpad. The SP3 has just the one, and with a small trackpad (and my fat hands), I use the single port for an external mouse. I know I could use a Bluetooth mouse, but that drains the battery even faster. And so, why do I even keep the SP3 around? Because I love the darn thing. I love the screen resolution, the pen, the tablet-ability, and (all things being equal) I am in love with Windows 10. But I gotta tell you, the battery drain on the SP3 stretches my patience, which for now lasts a little longer than the battery on the SP3. Any claims by MSFT of long battery life are specious in my opinion.