If I were you, I would avoid at all cost buying via Download, especially from Atari website, there are so many problem with that.
I did that, and they gave me an Activation code and an Unlock key that's not even valid.
I contacted them many times by emailing them, and it's almost always an auto-reply.
And they actually answer to you email, they are asking the same over and over, or they simply say that they can't help, contact, digital river etc. blabla..
And if you're lucky, the activation code and unlock key might be valid ones. But, not everything is solved. When you happen to reinstall your system, change computer or something in the hardware, the activation might not work, since they consider it as if you switch computer. When that happen you might have to call them to get a new one.
I heard it's very annoying since, nobody's there to answer, and it takes forever.
I know some ppl who fight for months in order to get a new key.
IMHO, I suggest you bought a CD version, activation code will always work no matter where you ihstall your game. I bought mine from eBay, sure, it might cost twice the original price if you include the shipping, but in the end it's worth it.
I wish you goodluck. =]