Having looked through this project I would not recommend using it as a basis for learning how an iOS app is "done right", as they've deviated from standard iOS/Swift paradigms significantly. In particular, the use of ReactiveCocoa and MVVM creates an app that is structured completely differently from a "traditional" iOS app. They've also used (abused?) Swift's ability to define custom operators which results in a lot of code like this:
self.youLabel
|> authorBadgeLabelStyle
|> UILabel.lens.textColor .~ .whiteColor()
|> UILabel.lens.text %~ { _ in Strings.update_comments_you() }
Which again is very different from regular iOS/Swift code.
That said, I think this project is interesting to look at from the perspective of "this is what it would look like to go all-in with ReactiveCocoa and MVVM". It's kinda like Twisted in Python: Twisted code looks very different from normal Python code, cause once you start using Twisted, it becomes Twisted all the way down.