I'm of the "do both" camp. Personally, I like starting out the interface in .xib because of the wysiwyg style - I've been an Illustrator and Photoshop design gu

I'm of the "do both" camp. Personally, I like starting out the interface in .xib because of the wysiwyg style - I've been an Illustrator and Photoshop design guy for much longer than I've worn my iOS Dev Hat. By laying out areas of apps in subviews of the main view, then manipulating those in code, I get very easy content sizing (3.5" vs 4" screen) without using the springs/struts and the terrible iOS6 autosizing constraints, and animations couldn't be easier. Just looking through my open projects right now, all of my ViewControllers have a buildUI method right under ViewDidLoad.