Some people hate interface builder and don't use it at all. I really like it and would have a really hard time getting rid of it. The amount of code you would need to write to make all of your views would be terrible.
I would liken it to not using HTML when you're making a web app and you can only use javascript to generate (by hand) all of the UI.
Except that I feel the control you lost by using IB is smaller compared to the control you lose by using an HTML builder. But then again, it's been forever since I last used an HTML builder.
In both cases, there are border cases that need to be handled in code (or markup).
I quite like Interface Builder, and this sounds like a bit of a deal-breaker for me. I'd rather not have my controllers cluttered with UI-positioning code, etc. It's a much more elegant way to create you UI (most of the time).
In relation to working with Appcelerator or a similar system that allows you to load in images/views/visuals & position programmatically, I wouldn't say it's a problem, more a shift in practice.
I would liken it to not using HTML when you're making a web app and you can only use javascript to generate (by hand) all of the UI.