Your odds are not 100% that the Assassin's Creed Coupon will work. Whether you get that via nVidia of Samsung there's a lot of unhappy gamers out there. The coupon is for the Ubisoft store. Even without coupons they have plenty of issues. Now if it was a Steam code, buy away.
TL;DR, Don't buy this 660ti if having AC3 with it is an absolute must.
I got my digital copy of assassin's creed included with my GTX 670 in under 20 minutes. Don't say that because you were not able to redeem it every one is...