I was looking to upgrade my 3.5 year old 10' atom cpu netbook to something with more power since the thing lags a lot even after a complete wipe/restore to factory settings. I am used to the portability and battery life of a netbook so I would be looking for something similar which brought me to the 11' macbook air. I was wondering if anyone out there uses the 11' as their ONLY computer? Does it have enough to act as your main and only computing device? Would you recommend it for me over the 13' since I value portability so much? The only issue I see so far (but I am highly unexperienced at macs) is the fact that the 11' only gets 5 hours of battery life. I guess 5 hours of productivity before charging should be enough? Or does the 11' get even less than this when browsing the web via wifi? On my old atom based netbook it was listed at 7-8 hours of battery life. I know the 13' has 7 hours of battery life but I'm not sure about the portability of it If enough people really advise against the 11' as their only device then I might end up going with the 13' so any advice would be appreciated, thank you.