What do you use for high fidelity iphone prototypes? A few things I've experimented with, and reasons they've left something to be desired:
Invision, Keynote, omnigraffle - can't add fixed elements (headers, tab bars) - invision & omnigraffle don't work for prototyping interactions or animations - keynote allows for animation and interaction, but there's no way to create long, scrolling, screens, and you cant run the keynote in full screen portrait orientation on an iphone, so you can't test the animations on the phone.
Proto.io - lot's of advanced functionality for interactions, fixed elements, etc.
Stuff I haven't tried yet but am considering. Does anyone have any experience using these?
http://www.framerjs.com/ - mainly geared towards prototyping interactions & animations.
http://maker.github.io/ratchet/ - html / css / js framework for iOS prototyping
Interface builder / Xcode - Straight to the source. How well does interface builder lend itself to using semi-static UI elements sliced from photoshop?