I haven't gotten too far with my test 13" MBA. I booted it up and installed Xcode -- it took about 2 hours to install, which I don't understand. Now that it's installed I can't build my project without recompiling some dependencies so will be some time before I can properly compare it to my Intel 13" MBP on things that matter to me (compile-run-iterate on iOS apps).

If you have any specific questions about software or task speed I'm happy to answer though!