IB is ok for getting started but it will eventually hold you back. If you get to the point where you feel like you're fighting it as much as using it then look into doing your layouts in code with one of these libraries:

https://github.com/SnapKit/SnapKit

https://github.com/robb/Cartography

It may take a little getting used to but, especially for the kind of dynamic apps people want to build today, it will save you a lot of time and headaches in the end.

Also make sure you get your head around UIStackView. It's a little tricky to learn at first but makes a lot of common layout problems easier to solve.

Also, start using this library ASAP:

https://github.com/mac-cain13/R.swift

As someone learning the basics of iOS development, I'd suggest you stick with IB. I get that most people either love it or hate it but there will never be a WYSIWYG editor that everyone will be happy with and there are ways it's lacking. But to call it a toy for demos is simply over the top. I've personally made pretty complex interfaces using iOS's auto layout using very little UI code.