Ordered the 13-inch. But it was really hard for me to choose. Originally I even put an order on the 11-incher but backed out.
First off, I've had a 1366x768 display before. (On a 15-incher, myah!) The PPI on it on a 11-inch screen is CERTAINLY ok but I know how much screen-estate it will be in applications such as Adobe After Effects and I know I will come to find it annoying. The small bump up in resolution on the 13-incher will make some difference here, I believe.
Second off I want the expandability that comes with an SD-card slot. An SSD upgrade costs a ton, and my portable video/music/document library won't benefit much from the speed. Now I just need to wait until November and then I'll hopefully have the "Nifty Minidrive" + 64GB Micro SDXC.
And third I believe the battery of the 11-incher won't survive my work day.
In the end the 11-incher's size wasn't enough of a reason for me, although very tempting. I can certainly see and understand the rather big niche that values the smaller footprint, though.