I have the same Mac Pro, except went with the D500 and invested the savings in upgrading it to 64GB of RAM.
It's my daily "go to" machine for everything I do at home, including occasionally working from home doing computer support and network administration for my employer.
I used to care more about gaming but find as I get older, it's just less and less of a "thing". I think this is partially because at my age, I feel like I've "been there, done that" so often when I play a new game title. I'm part of the generation that grew up with the "classics" like Pac-Man, Donkey Kong, Asteroids, Qix, Zaxxon, Defender and Frogger. It's great seeing how far gaming has come from those days, on one hand. But on the other, I see so much repetition now. 99% of the 3D shooters are the same, tired game-play and mechanics, wrapped around a slightly different story-line. Almost all the car racing games fall into 1 of 2 categories; your "big name race" simulators where you see if you can get the best time around a course, and your "street racing" games where you've got the stereotypical "sexy women" and "cool dudes" betting money on winners so you can spend it in-game on car upgrades and accessories. And fantasy RPGs have never changed... I imagine by the time I retire, they'll be on Diablo IX or X, Final Fantasy 100, etc.
I'm to the point where I'd rather have the overall superior machine that a Mac Pro workstation is (near silent operation, stylish and doesn't take up much space on my desk, unbeatable for "pro apps" like Final Cut Pro X or Logic Pro X, etc.) -- and just play the games that DO come out for Mac, if they look interesting. Few though they might be, they're usually the "proven popular" ones that come over from the Windows and/or console side of things - so they're rarely a "dud".