#1 is saying that you're restricted to point based UI's in interface builder. This is absolutely not true. Wether you do you UI's in interface builder or code - use auto layout!
This way you get dynamic, resolution-independent UI's that can even work automatically with right-to-left text (realigning other elements according to text alignment).
The way the author is doing it is still point-based (just a bit more dynamic since he does some calculations) while auto layout has all this built in.
Yes, it is harder to get started with auto layout, but once you learn it, it is worth it.
#2, using things like UIView+Positioning still sets your frames. And it does so for each property you set. This means that the frame might be set 5 times instead of one (just for slightly cleaner code). This is not good since it might cause 5 calls to layoutSubviews instead of one (performance issue) and also it will ruin animations (dependent on a source and target frame).