If you are going to get just one game, get THE CREW. Driveclub's graphics are not worlds better than The Crew's. I'm not too sure the physics are more real as well -- because I played a demo of Driveclub and it seemed too easy to drive! I usually suck at driving sims.
The Crew on the other hand has much more play value. It's an RPG and you are free to play with it any way you like: if you can discipline yourself to drive yourself around the map rather than use the Quick Travel feature to jump around -- you can. Else there's that shortcut. In the beginning you WILL get a sloshy car - IF - you choose one -- so don't go for that rad Chevrolet when the Nissan Skyline handles better, though not as posh-looking! That's why you get to test-drive all the cars before you buy! I had a really great time figuring out things in The Crew and that's the beauty of RPGs: when you get it, your proud you got it. Time well-spent. And then you go out for more. The beauty of The Crew is in the scenery -- and with free drive "mode" (it's all free drive really) you can check it all out at your leisure. The freedom to go wherever you want to go -- drive wherever you feel like -- that's what makes The Crew a game worth getting a wheel for -- even though it's an arcade racer.