Long-term usage experience: good, bad, shortcomings?
I do have some concerns due to the lack of user-replaceable components -- for those who have been using MBA for several years (starting from previous revisions), how durable are the SSD and battery? I'd need to get it shipped to a different country -- no CTO in Indonesia so I can't get 8GB -- so if I make a wrong buying decision it'd be hard to rectify it.
Couple things if you want to use it as a primary machine:
-Don't get the 2011 version. Get the 2012 version for USB3. Although the 2011 version has Thunderbolt, USB3 devices are more prevalent (and cheaper).
-Get the thunderbolt to gig ethernet adapter (or a 3rd party USB3 to gig ethernet adapter). 802.11n is okay for casual use, but if you want it to be an almost desktop replacement, nothing beats the speed and reliability of wired networking.
-4GB RAM is limiting though. Can you BTO from Singapore?
If you can wait, I would wait for Haswell (plus with Haswell's beefed up integrated GPU, the 13" rMBP will be more tempting). Also, it would be interesting to see the plethora of Windows 8 tablet-hybrids with the low-powered Haswell/next gen Atom.