What a pile. All it is is a web browser. That’s pretty much it. And a poor one at that.

Instant beefs:

• It installs games as hidden files not applications.
• It runs a process named ‘ipcserver’ that remains alive after you quit the client.
• The UI is non/sub-standard.
• It doesn’t clean up after itself if you relaunch after force quitting it which then prevents it from starting* (though the ‘ipcserver’ seems to have no trouble starting).

To overcome that last item (which throws an error stating “steam engine instance already exists”) you have to manually remove a couple of files from /private/tmp. In Terminal type rm /private/tmp/*-steam-mstr-* and press return, then launch Steam.

*[UPDATE] Newer clients (the About window doesn’t actually list a version. More Steam on Mac “goodness” 😐 ) will launch after a force quit by apparently recycling the left over files which needed to be removed manually before.