I was going to stay out of the MacBook Air discussion given the vast volume of discussion already online. However, I was more than a bit surprised by the negativity of so many posters and commenters. As an often "road warrior," I thought it pretty interesting--even if it does skirt the edge of excessive compromise in service of thinness.
First, by way of background, I like small notebooks. My current model is a Fujitsu LifeBook P5020D. Although I don't use my notebook only when traveling, it's definitely a supplement to my regular desktop. In fact, when working at home, I often just use the laptop through an RDP session from my main desktop system. As you may gather, I'm not a Mac user but the MacBook Air feature discussion isn't really about anything particular to Macs.
So, let's go through some of the MacBook Air's features and see how they would fit in with my specific usage scenario. Your mileage may vary, of course.
Form factor. Very thin. Very sleek. Lightweight. 13.3-inch widescreen display is nice. (That's a bit larger than my Fujitsu's 10.6-inch screen. I used to think I preferred the smaller screen so that I could work in planes but I find this hard to do anyway and I've come to think it's just a bit too small.)
Full size keyboard. Also nice. That's one of the things I just don't care for on my Fujitsu which has an approximately 90 percent-sized keyboard.
Large trackpad. My preference is for trackpoints a la Lenovo, but I've come to accept that trackpads are more common. I can live with either approach.
Now we get to some of the compromises.
CPU. The MacBook Air uses Intel's Core 2 Duo (1.6 or 1.8 GHz) in some special packaging. This is no speed demon but it seems that this would be quite adequate for my purposes. I don't do things like heavy-duty photo editing on the road although, truth be told, I would guess that this processor is probably at least as speedy as the AMD Athlon 64 3000+ processor that I do use for photo editing at home.
Non-Upgradable 2GB memory. Even by today's standards, this is a pretty healthy complement for most purposes.
80 GB 4200 RPM disk. This I'm a bit less thrilled with. I upgraded my Fujitsu's drive to a 5400 RPM model a couple of years ago. Nor is 80 GB a huge capacity even for a traveling notebook (especially if you want to carry a lot of video around with you). The good news is that I expect we'll see higher capacities coming down the road. The 64 GB solid state disk upgrade is pretty useless for most purposes today; it adds something like $1,000 to the price.
No built in optical. This one seems to have a lot of people up in arms. I rarely travel with the optical drive for my Fujitsu. (I put a second battery in the bay.) I rather like the sound of the whole Remote Disc system. I don't personally have any issue with the lack of an integrated optical drive.
Integrated (non-removable) battery. This one concerns me. I do travel with a spare of my Fujitsu's main battery. (So I actually travel with three batteries: two main batteries and a drive bay battery.) It's often hard to find power at conferences and it's nice to be able to go a full day without plugging in. That said, for all those batteries the Fujitsu still only gets maybe 7 hours or so with WiFi on. (It's a pre-Centrino laptop and the WiFi seems to be a considerable power hog.) So if the MacBook Air truly gets an honest 5.5 hours of battery life, that's not too bad--but not great either.
One USB. Again, not thrilled. I tend to use my laptop to charge a lot of my mobile devices. This probably means carrying a small USB hub with me.
No Ethernet. Increasingly not a big deal but I'd still need to travel with an Ethernet adapter to connect to the USB. The WiFi sometimes gets overwhelmed at conferences when there's still Ethernet in the Press Room. And you still need to use wired Ethernet in some hotel rooms. (Apple will also sell a USB modem but I can't remember the last time I used a dialup connection when traveling.)
No card reader. I sometimes use this to transfer photos but I suppose I could always just connect the camera to the computer.
No ExpressCard or other expansion capabilities. After consideration, this is what might concern me the most. It means that you can't plug in a card for either cellular broadband or for WiMAX. In practice, you may be able to get to cellular service by plugging a telephone into the USB. And perhaps WiMAX could be added at some future date through a USB-connected device as well. But about the best you can say is that the lack of expansion means that you won't be able to add new networking options to the MacBook Air as easily you would with chubbier laptops.
Price.Yes, it's on the pricey side but that isn't a major consideration for me (within reason) if it's the right tool.
If I were to replace my Fujitsu with a Mac, I would certainly consider a MacBook Air. Albeit not without some qualms. It does push the envelope hard and makes some design tradeoffs that not even all its target users are likely to be comfortable with. For myself, I would have to consider some of those tradeoffs carefully. But they hardly seem irrational.