9.12 drivers vs immature drivers is pretty damn equal. In the BEST case 10.3 adds UP TO 15% better performance. As you can see its not a big deal. For fuck sake do you want me to do the math for you?
The current Nvidia drivers for the 480 are very mature by the way, lets look at a timeline
5month ago, (a few weeks after the great successful 5870 release, although short in units) Nvidia release a public statement stating that they were done with the Fermi project and had "foundry issues" for producing large volume, this was a corporate lie/cover up. Im telling you right now (and there will be no source to back this up bc its speculation although I am experienced in business) that the issue was the foundry made their card and they got it, tested it and it SUCKED, they then spent the next 5 months working on the software side and thermodynamics of things (this card looks a hell of a lot different that initial photos of the card. ) They couldnt re-engineer a new architecture or adjust their own becuase nvidia is cheap, and signed a contract with their chip maker (who made dies already) that the dies would be used for x amount of cards.
So, in my opinion this card is the final mature, "the best we could manage" from the green camp, so really these drivers vs. the same amount of time ATI had to "mature" theirs is extremely equal.
Fermi has been done for a long time, the release only came when their accountants said, do it now or lose more money. Honestly, you get DX11, and Tesselation, gogo! As one other thing (I do not know all the differences at all) has the quaddro version of fermi been out for a while anyways? similar basic architecture right?