I wouldn't call the TZ a marvel.... I have one, cramped key board very small screen, very slow operation (XP or Vista)...it is a nice sub notebook, and has served me well, but trying to open two windows on the thing and typing more than a paragraph is painful. I just got my air and in my opinion the build quality is much better the keyboard is heaven and i love the screen. And its running OS X and is even pretty snappy with Vista in VMFusion. Give the decision to offer a 13 inch screen and full sized keyboard seems to have been paramount i think the engineering Apple put into it is impressive, and I think its looks soooo good.Not really. A Sony TZ is an engineering marvel, relatively speaking. An Air is merely a marvel of marketing combined with the best that Apple can do in terms of shrinkage. They've taken the usual Apple 'smoke & mirrors' approach, this time making the machine look razer-thin by sticking with an almost-normal-laptop area. A true subnotebook with the same vertical dimensions wouldn't look as thin to the eye.
However it has a use for us business types who doesn't need the power of an MBP but likes to carry lighter stuff. To my Windows eye it's a bit crap, but it's the only choice I have for a truly portable OS X machine. I also think it's the prettiest Apple laptop out there, but that is subjective, and subject to review after I've used the Airs for a while.