[cstross]

Performance v. weight with the Macbook Air is currently easy.

The real issue is battery life/screen size (on the move) v. weight.

The top end 13" and 11" Airbooks both upgrade via BTO to a dual core i7 clocked at 1.8GHz, with 4Gb of RAM/256Gb SSD. The difference is in screen size and battery life (the 13" model has more of both) and weight (the 11" wins here, by 300 grams).

If you're out of the office and working on the laptop a lot, or don't use an external monitor, I'd go for the 13" model (unless weight and the ability to work in very cramped spaces are an overriding priority).

If you're in the office a lot with laptop plugged into a desktop monitor, or if you don't do much work outside the office (just need the laptop to check email/web/social networks), then the 11" model wins.

But they seem to be a tie on performance, which makes life a little easier than when they first launched (the 11" was, even maxed out, slower than the 13").

[SoftwareMaven]

My performance calculation is MacBook Pro 13" with 8gb RAM versus the 13" Air with 4gb. The 13" is a must for either, but the decision comes down to less swapping and more horsepower versus less weight.

I wonder how much impact SSDs have on swapping. I rarely need 8gb of active memory. I just can't stand waiting minutes for things to swap around right now.

Time for more research...