If the MBP appears prehistoric then the Air is like an artefact from the future. The kind of object which is so perfectly engineered as to seem not manufactured at all but instead brought into existence fully formed.
After much deliberation I had ordered the 256Gb i7 version. I had been worried about heat - based on reports of the i7 running hot. However although it is warm to the touch it is much much cooler than the MBP which, if performing light duties for an hour or so, would become uncomfortably warm (i.e. hot) to type on. The underside temperature of the Air in general use on my lap seems to stabilise at around 32C whereas the MBP would generally run at an uncomfortable 39C.
I set up the Air by performing a migration from the MBP's last Time Machine backup. This was relatively quick (around 1.5 hours for 150Gb over USB). It all went well except some App Store purchased programs needed to be deleted and reinstalled before they'd run.
Compared to the 5400 RPM disk in the MBP the Air's SSD makes everything I/O-related blisteringly quick. The keyboard is lovely. The screen is nice and sharp although its brightness does seem to need to be turned up relatively high in order to be usable - probably a reflection of my tired old eyes.
The SSD really shows its mettle when using big bloated Java IDEs like Netbeans which loads very quickly and even though the screen is small it is still very usable. It's also transformed my use of virtual machines. Starting or resuming the Windows 7 Fusion VM on my MBP would essentially hang the machine for five to ten minutes. On the Air the VM starts, runs, suspends and resumes very quickly and without unduly impacting the performance of other processes on the machine. It's a shame that the memory is fixed at 4Gb but it's enough for me at the moment.
I have a real dislike for glossy screens. They look particularly bad in brightly-lit environments such as, ironically enough, Apple stores. However, the Air's screen is much less glossy than that of the iMac or MacBook Pro. So much so, in fact, that I can't say I've yet noticed a reflection at all. Good stuff. The text is a little small and would probably rule out its use as a primary machine for me.
Although pre-Lion versions of Mac OS X supported encryption of a user's home directory this ability came at the price of limited Time Machine functionality. However, Lion's full disk encryption together with the Air's SSD and the i7's AES-NI hardware accelerated encryption delivers security which is seamless, Time Machine compliant and performant. Benchmarks show that it has minimal impact on system performance and battery life. Full disk encryption is clearly especially useful on a machine which is as eminently nickable as the Air.
The much touted instant is not noticeably quicker than my old MBP - or indeed any of my previous Mac laptops.
I haven't done any formal battery life tests but it lasts much much longer than my MacBook Pro which itself has a relatively new battery.
It's shame that the Air doesn't include a 3G wireless chipset but I'm guessing that Apple left it out as it would crush battery life.
It's also a shame that Apple/Intel haven't adopted USB3 because, as things stand, there is no fast storage option for the Air - I don't count the Thunderbolt display because a) it's not actually available yet and b) explain why I need to spend 800 quid to get a Thunderbolt-to-FW800 convertor?
I ran a quick performance test by encoding a 720p movie using Handbrake. My Mac Pro (2.26Ghz Octo, 16Gb RAM) averaged around 60fps whilst the Air averaged around 20fps. A pretty creditable performance.
Pros
Light
Good battery life
Super quick
Quiet (mostly)
Cool
Cons
Fixed 4Gb RAM
No USB3
No 3G
Verdict: Lovely jubbly.
