In my experience, it's difficult to go through because it's so comprehensive and thorough, and I guess it has to be because it has to assume the lowest common denominator audience. Personally I'd like a shorter guide that assumes you know a few languages (C#, ObjC, JS, Java) and skips a bunch of the tedium of how programming languages work in general and gets right to what's different about Swift. It may seem like it does that, but look at their page about control flow[1] and tell me it's not an unreasonably long-winded way of explaining switch, for, for-in, while, break, continue, and if.

[1]: https://developer.apple.com/library/content/documentation/Sw...