I would still recommend using Auto Layout, even if you are laying out your views without Interface Builder. (Full disclosure, I helped write Auto Layout.)

One advantage is that it makes sure things are pixel-integral, no matter the scale factor of the screen. For example, his code example,

button.x = self.view.width * 0.2; // Position the inset at 20% of the width.

has a pretty good chance at starting the button at x=21.845, or some other point in-between pixels and producing a blurry line. If you do this same relation in Auto Layout, the engine makes sure that the positions and widths are all pixel-integral.

This is not as simple as just rounding everything, either! For example, if you have two views

[blue][red], you want to make sure you round their shared edge either to the left or to the right. Otherwise, there will be a gap between them. You need to make sure you round their shared edge the same way consistently too, or it will jump back and forth as you resize a window and produce a noticeable jitter.

Also, in that same code example, they set a button's x position to be directly related to the width of a view. If you ever want to support RTL interfaces, this is a bad idea. It is relating a width to a position. In a RTL interface, the correct code would be

button.x = self.view.width - self.view.width * 0.2 - button.width

Complicated! In general, you shouldn't convert between positions and sizes. Instead, I would make an invisible spacer view and lay them out like this using the layout format language

|[spacerView][button]

Then make a relation setting the spacerView's width to be 0.2 of the superview's width. This will produce constraints that correctly work in a RTL interface, laying it out like [button][spacerView]|.