I just received a driver update, and it says that I get the "best day-1 gaming experience". I think that it should read day-one, as day-one is not stated as a specific amount of time, just the release day of the game.
If it was talking about, like, fifth day of the game (example:
Unfortunately, hacks were already released for the game on day-5.), I'd expect that.
The text reads:
Prior to a new title launching, our driver team is working up until the last minute to ensure every performance tweak and bug fix possible makes it into the game Ready driver. As a result, you can be sure that you'll have the best day-1 gaming experience for your favorite new titles.