Interface Builder was a lot more like VB and Delphi in the past, but around the time of iOS 3, Apple completely broke the UI programming metaphor in it. It used to be all drag and drop (with quirks) but actions were like event handlers and outlets like events. Before it was "code first" you could do it all in the UI. I used it quite a bit before XCode existed (XCode used to be ProjectBuilder, even on like Jaguar/Panther IIRC) and it was very close to the version of the same on OpenStep.

Xaml designer - well, the designer is not really a thing because Xaml is usually not created as an absolute layout. There was a version of the Xaml designer early on that would attempt to build a UI that looked absolute, but it did a lot of horrible Xaml markup in the background and made maintaining the UI way harder than it should have been. We (Xaml users) all migrated to using it as pure markup and mos of us now use hot-reload over a designer.