I'm chiming in...
I too, was in a quandrey as whether to get the Kira, or the Kristin zip top. For me, it was the fact I could wear the Kristin on my shoulder both ways. I have the black zip top Kristin. It's a bit 'glazier' than her sisters' leather.
It seems some of the previously posted cons on the Kira were it's size, puddling(some either like it, or don't), and not liking the long braided shoulder strap(some posted it wasn't comfortable). There are also those that love every inch.
The kristin zip top tote pros: elegant, large front pocket(for keys and iPhone), glazed leather(does well in wet weather), 2 different straps, size, look.
Cons: the clanking noise of the chain strap(I just take it off during those times it bugs me).
When I first saw the Kira, I thought it was huge. But, I'm a convert now, and love huge bags, even though I don't carry that much!
Both are beautiful. You can't go wrong with either. Just know yourself, and what you prefer.
Hope this helps!