Shortly after the 12" Powerbook was discontinued I decided to switch to mac. I definitely wanted a small computer, so I waited until apple released something light that I could carry anywhere.
I've been using the RevA MBA since Feb'08, taking it to and from the university everyday, virtualizing Windows XP to run simulation software for electronics, traveling with it along the world and using it as my only computer.
During this 4.5 years I had to replace the following parts: power adaptor, upper lid (monitor & hinge), audio flex cable and hard drive (upgraded to a SSD!). All of them I did by myself except the upper lid because it was a defect acknowledged by Apple.
For the last year or so, the computer has been running considerably warmer and slower (due to core shutdown). It's not a problem with an additional cooling fan underneath the laptop, but these days the summer has set in (specially here in Spain) and it's a real pain to work in such a sluggish machine. So when the revamped MBA appeared I decided it was time to update it.
I ordered a 11"/8GB/128GB within 24h after the keynote, and I'm still waiting for it, it's supposed to arrive on the 28th (yeah, we Europeans are second class clients for Apple

). When it arrives, and after leaving it ready to work, I'll open one more time the old MBA in order to try to repair it so I can sell it for a couple of hundred . As I've read in other posts, it's "just" a matter of cleaning the fan and replacing the thermal paste

.
Overall, I've been quite happy with the basic RevA MBA. Maybe not a perfect product but it definitely gave me more than any other computer brand at that time could offer me: a laptop with a 100% keyboard at a light weight with a great OS.