I see my RevA MBA as a long term purchase. It's designed and being used for a purpose which isn't hugely dependent on performance, so even as the years go on, I'm not going to be doing anything particularly demanding on it, whereas on a desktop or full-spec laptop I would be more sensitive to performance. For what I use it for, it's doing well, and I don't expect that to change much over the next 2-3 years.