1) The iphone version no longer has the "current search results" button. Thus, if you accidentally go back to "flights" and want to look at the results you got, you have to re-do your entire search. Quite painful.

2) Some results don't exist. I once saw Swiss SFO-ZRH in business class for $1900 round trip. Of course, it seemed too goo to be true. I clicked on the link, and it was $4000 each way on Swiss' website...

3) The iphone version calendar (when choosing dates for flights) coudl be scrolled up just by pushing it, like when you push your photos. But instead, you can only advance with the arrows. Very inconvenient.

The last iteration of the kayak app on the iphone was better than this current one. I wish I had never "updated" the app.