It's basically the same as the distribution from http://emacsformacosx.com, but it supports various enhancements made for mac, eg. resize text size with trackpad, smooth buffer scrolling and SVG support, which is quite convenient when used with the jupyter notebook interface and producing plots. See for instance : http://imgur.com/gallery/vEI2z.
I use this version too and have been very pleased with it. It's also available via Homebrew [1].
As an aside, I'm looking forward to better support for text scaling in future [2,3] as it's a feature that (if it was compatible with autocomplete and company-mode) fits my workflow better than zoom-frm.
I don't know. Probably not. The reason I install with dbus support is to avoid having packages that rely on it not working, should a package ever rely on it (maybe mu4e notifications? idk). Take imagemagick, for example, you can still display images with Emacs without it, but you can't resize them.
I've been using the Emacs that comes from homebrew with the spacemacs plugin (system? Total conversion?). Not a perfect integration when it comes to images but I stick to text and it's been great.
As an aside, I'm looking forward to better support for text scaling in future [2,3] as it's a feature that (if it was compatible with autocomplete and company-mode) fits my workflow better than zoom-frm.
[1]: https://github.com/railwaycat/homebrew-emacsmacport
[2]: https://github.com/company-mode/company-mode/issues/299
[3]: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=18493