I have a 2009 macbook unibody i use everyday for work. It is well bit heavy in bag everyday. I found an 11" i5 air with 4gb ram and 256SSD My only worry is at present my macbook has 8GB of ram and regularly uses little over 4GB ram with the apps I use at work. I can cope with smaller screen that not an issue. but hitting the ram limit might be. Should stick with my old macbook until i find a better unit? Just not sure 4GB ram be enough if I'm using about 4.3 to 4.6 in my current machine.