I think your understanding of your system is flawed. Taking ownership of /usr/local is a suggestion it isn't a requirement.

It seems the anti-homebrew complaints basically amount to "I don't understand this, so I'm going to say it's bad".

The biggest reason I've seen to get rid of Macports in favor of Homebrew is software versions, Homebrew is constantly up to date and I can upgrade software with ease. Not so with Macports.