Mind I asking why you decided to go from 11" to 13"? Pondering going the other way (and haven't received mine yet)
I find the 16:9 screen ratio to be awful at 1366x768.. I think it has a lot to do with how OSX is presenting itself to that resolution.. You don't fit a lot of web page and reading on the screen in that narrow of screen space.
The 13" is so much better for viewing content, but less so for movies/tv but I don't care about that.. I like to surf, read, and have more screen real estate.
11" keyboard palm rest is shorter and even though its still a full size, I found where my palms rest it just wasn't comfortable to me for long term typing.. The 13" has wonderful ergonomics, YMMV.
Everything else about the 11" seemed perfectly fine.. Speakers sound pretty much identical to the 13", battery life equally terrific.
I just definitely feel more at home on the 13".. I always went for the tiniest powerful machines I could find.. But to seriously use the 11" and feel like I could put a full 9 hour work day on it.. Not for me.. I don't think I could do it.. The extra res on the 13 is much better as a work horse.
The last thing is that people seem to be getting more Samsung LCDs and Samsung SSDs in the 13s over the 11.. This screen has deep blacks, whiter whites... Looks like Apple quality again.. I felt ripped off when I had my 11..
Glad I went back to 13"