I tried to use autolayout in Interface Builder and finally got my fairly simple login screen to work but I cussed at it the whole time. Move a control, have IB tell you the constraints and form are out of sync, correct it and repeat. If you move a control that was used as a reference anchor for other controls then it got really lost. You end up manually deleting constraints that show up either below the control you are moving or maybe at the root view. Just way to painful and error prone.
Here is where https://github.com/Masonry/Masonry comes into play. I have used a number of layout managers in the past including standard Java layouts, MigLayout for Java and the Android XML layouts. Masonry is similar to each of them in a number of areas.
A new layout with about 35 controls was the tipping point. No way I was going to do that after all the venom I spewed at IB doing the login view with only 7 controls. I got the new layout working pretty quickly in Masonry then I went back and ripped the login from IB and did it in Masonry where I can easily see the exact constraints and view relationships.
Not a huge fan of checking in the code for iPhone vs. iPad but for a universal app where you want special layouts that is what you get to do. Not sure what will happen when the new iPhone 6 comes into play.
I am now skipping story boards and all their headaches and just doing my layouts in code. This also means is a new developer was to come on board we would not be walking on top of each other when we change a layout which stinks with storyboards and version control. That developer would get to learn Masonry but it is reasonable straight forward. I still run into some odd layout issues that send me scrambling to stack overflow but in general it has been pretty smooth.
UIScrollView gave me the most fun but once I figured out how to anchor the scroll view to the main view then anchor child views of the scroll view to the scroll view it all worked out.
The error messages given by autolayout are not super helpful. Some trial and error is involved but I don't run into errors very often anymore.