It's not a big deal precisely because Apple has been firm about just 2 logical display resolutions (iPhone and iPad) and using pixel-doubling automagically.
No. It's
3 logical display resolutions not counting the scaling factor.
320 x 480 for legacy iPhones.
320 x 576 for iPhone 5 and iPod Touch 5.
768 x 1024 for iPad and iPad Mini.
Add scaling factors and DPI-dependent scaling (exact physical measurement on screen) and you have just as much fragmentation on iOS as you do now on Android.
I'd bet you've done a lot more Xcoding than I have, but you have some of this stuff backwards. Why would you hand code your UI if you can visually lay it out with IB?
I'd hand-code my UI if I have to deal with contents dynamically loaded from network... which I do... in every project that I handle now. You never know when an image you are loading from network is bigger than your layout.
Also using hand-coded interface allows me to incorporate my own APIs into the design of the app to circumvent the limitations imposed on Apple's APIs. For instance, Apple has not made an official API that can display rich text (colored, bolded, italicized, etc...), and anyone wanting to display multiple types of text in the same dialog box needs to make their own text class. Simply put: have fun writing your own "Microsoft Word" app.
Also it's easier to manage resources and free up memory when necessary... as opposed to having to account for things by repeatedly counting. That's not good when you are trying to conserve CPU usage.
Last but not least, the flow of the app is clearer in code to me. Interface Builder has way too many unnecessary connections and links that I have to individually assess and analyze... It's good enough for apps that are not too complicated, but not for apps that do more advanced stuffs. You definitely won't want to make a game in Interface Builder. I've been there... done it, and now I swear off Interface Builder like the plague.
As an aside, too many views and windows created in Interface Builder can cause XCode to crap out eventually.