When comparing MacRuby: The Definitive Guide vs Why's (Poignant) Guide to Ruby, the Slant community recommends Why's (Poignant) Guide to Ruby for most people. In the question“What are the best resources to learn Ruby?” Why's (Poignant) Guide to Ruby is ranked 6th while MacRuby: The Definitive Guide is ranked 27th. The most important reason people chose Why's (Poignant) Guide to Ruby is:
Available online for free.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Free
Available online for free.
Pro Entertaining
The book includes drawings and jokes that can make the learning process more enjoyable.
Cons
Con Outdated - Material is no longer very relevant.
MacRuby is not the best introduction to the Ruby language, as it was meant as an introduction to MacRuby which is an implementation of Ruby 1.9 on top of the native Objective-C runtime and CoreFoundation framework of OSX - and is not just the RUby language itself.
Furthermore, wiith the recent dump of Objective-C by Apple, most of the libraries that MacRuby was built on top of no longer exist in OSX distributions, so the project is effectively outdated. Refer to the referenced Readme on their Github project for more information.
Con Entertainment can be distracting
Being entertained while learning is not for everyone.