Although I don't use OS X more than a few hours per month, this person has it right. The key thing to keep in mind is that OS X is UNIX. Sure, the command-line

Although I don't use OS X more than a few hours per month, this person has it right. The key thing to keep in mind is that OS X is UNIX. Sure, the command-line tools it comes with don't always support GNU extensions -- fine. And the package mangement is iffy, at least as far as GUI applications go. For the command-line, a lot of people swear by package managers like Homebrew, probably because they also help resolve the "no GNU extensions" problem. While I don't use OS X enough to have any experience with this, I think this would be the key area for me to investigate to before I'd be comfortable using OS X as an everyday system. The rest is just getting comfortable with the keybindings/modifier key layout. To elaborate on the modifier keys, from the inside out: Command key for GUI shortcuts (⌘C, ⌘V); Option (same as Alt); and Control. Both Option and Control are rarely used by themselves (though the Option key can be used for special characters and the Control key can be used for Emacs-style editing shortcuts) and can pass through in Terminal -- this is where the separate Command key really shines. Oh, and the window manager. Coming from Linux, one of the strangest things about OS X is probably the application-oriented focus model (rather than window-oriented). As the parent mentions, this manifests itself in both the dock (clicking on an icon in the dock raises the whole application) and the hotkeys (Command-Tab to switch applications, Command-Backquote to switch windows within an application). This takes some getting used to, but like with the keyboard shortcuts, it should only take a day or two. On the other hand, the OS X implementation of workspaces is very good, especially if you decide to run a VM. So to summarize, OS X is still a real UNIX system with a real command-line (and development tools are literally one click away -- type gcc or make or git into Terminal, and then click Install). It just has a slightly odd desktop environment on top, but that shouldn't be too hard to get used to.