Sorry, from my personal experience that still isn't true, as much as I wish it were.
To make a long story short: we could exchange anecdotes all day about the state of 'Just Works' on Linux, but at the end of the day, I think no one with enough experience using various Linux distros and OS X, can honestly and sincerely say Linux is even close to OS X in that aspect.
Myself, I've been using Linux since Slackware 4 and have tried about 10 different distro's over time, alongside OS X for the last 5 years or so. Up to this day, I regularly run into problems that need fixing on Linux, particularly after upgrades, or when switching hardware. Whether it's Wifi cards, USB hardware, multi-monitor support, network configuration issues, software that stops working, system library problems: there's always something. OS X on 3 different machines, from OS X 10.4 through 10.7, I've only had one issue that required maintenance once, on a b0rked upgrade. It was pretty nasty, but fortunately OS X has Time Machine and target disk mode, so in no-time I was able to pull off any important data just to be sure, re-install the OS, restore my Time Machine backup, only to find out everything was back to normal, to the point I didn't even need the files I had to pull before the restore.
I said if you spend a little time scoping these kinds of things out up-front, it's very easy to get a machine on which it will work without issues. Obviously if you found a machine lying around the office and tried to load an OS on it, your chances of it working well are not going to be as good. You can't just load OS X on random hardware and expect it to work either.