My main workstation is a two year old Air, with no problems so far. I expect it to last me another year, maybe more. My needs may be simpler than yours, though:

My main workstation is a two year old Air, with no problems so far. I expect it to last me another year, maybe more. My needs may be simpler than yours, though: mostly I just run emacs and web browsers. I rarely use memory-hungry IDEs, and never edit video.