While considering new laptop, I run xbench on my almost 3 years old MacBook Pro against half a year old MacBook Air (the one that belongs to my wife). While a lot of people think that xbench can't be used as accurate comparison test for computers, something is better than nothing.
So here comes the data side-by-side.
As you can see, the overall score for MacBook Air is about 2 times less then for my MBP.
Going into details, the CPU scores are pretty close to each other. I don't know why but it could be that 1.6 Core2 Duo is running much alike 2.0 Core Duo. Memory test is also pretty much the same.
Graphics really sucks on MacBook Air. Especially, when it comes to OpenGL.
One of the biggest surprises was that disks are running pretty much the same, however, my MacBook Pro was supposed to be 5400rpm vs 4200rpm on MacBook Air.
Keeping in mind that market price for my MacBook Pro is about $1,000 off the craigslist, and one can grab a sealed first generation MacBook Air for as low as $1,150 (add taxes, AppleCare and other shit and it will grow upto $1,500), the price difference of $500 could be a good bargain for getting 3 years hassle-free laptop. However, you should be ready to depart with all-in-one laptop, loosing bigger 15.4" vs 13.3" screen (not a big issue for me though), Firewire port and integrated SuperDrive (that's basically all that I'm really using). The gain is lighter weight, slimmer and fancier toy. ;)
So does it really worth it? I don't know. I'm still looking for aftermarket few months old aluminium MacBook Pro's, which are priced around $1,800-1,900 off the craigslist (no taxes, but add extra $250 for AppleCare). The upgrade cost is raising two times up though.
I'm missing old good days having few more years on AppleCare and caring less about what I'm working on. ;)