Great:
- Abundance of screenshots
- Very step-by-step & granular
- Love the description of the Terminal & the clear delineation of command-line bits
- The Homebrew output is excellently searchable (not just in screenies)
Would Change:
- You're covering multiple versions of OS X in the same document. Given how things have changed, I'd separate them into different articles (with links between them). That way it's more focused, shorter & less confusing.
- Covers the newbie excellently, but the advanced user is going to have a bit more trouble skimming. A quick-start at the top (just what you need to run all as a single block, best-case-scenario style) might be nice.
- I'm not sure a blog post is the best way to handle this kind of tutorial. The reason is that it's very difficult to see the historical information associated with updates. Something that incorporates versioning (blog-post-via-git-and-github, wiki, online editors like etherpad) would be a nice addition, both in the free indexing by search engines as well as for users coming back. It'd also save on length of the article.