For me Kierland is much, much easier to get to than Scottsdale Fashion Square and delivers the bare essentials that I need for shopping. (BCBG, Charles David, Banana....I'm set.) There are quite a few restaurants located within the commons which is nice, I love being able to walk around after a good meal. I dig that its an outside promenade, it gives it less of a mall feel. I've never had a problem with parking here, there always seems to be spots.
If I suddenly find myself in need of an outfit asap I know that I can just zip over here and I will find what I need.