I still use my original MBA (ssd) and love it for the light weight, as I take it up and downstairs frequently during the day when researching fabric inventory issues or selecting fabrics for a project. It does not get heavy duty call on its capabilities. No overheating, no hinge issues that I am aware of. I sometimes rent movies from iTunes onto it, outside of that it's mostly browse / email / local net looking at data pulled over from another Mac (from Bento info or some spreadsheets). I don't even bother backing it up dailiy, might export a few files at day end; once a week or couple weeks I back it up if I have done any software updates, but it's back on Leopard still so that's a rarity now.
The battery is probably not what it used to be, but it's not down to an irritating level yet. I just keep an eye on its performance month to month, top it off early in the morning and it's good to go for the use I put it to during the day. I have noticed that if I put it to sleep and let it sit for a couple days it drops off a bit more than some of my other notebook Macs do or have done in the past. Some of the early MBAs had battery or charging issues right from the beginning, I think, but mine seemed fine.