Yes Amazon does give the $15 promo credit when you pre-order, but it's not towards the purchase of the game itself. The promo credit isn't added to one's account until after the game is shipped. So it will still be full price on Amazon as opposed getting the $15 knocked off right with the promo code on Newegg.
Problem with New Egg is they don't have release-day delivery, and in my experience with them, I've received games 2-5 days after release. Plus, I have Prime, and free 2 day/release day delivery is better than getting the game 4 days later, IMO.
I don't mind the wait and last year I would get my games either on release day or the day after. I wonder Newegg doesn't ship 3 days in advance anymore. I would like to have Prime too but can't afford it right now. I have the 30-day trial going, but I need to cancel it shortly after NCAA Football 13 is released.
Amazon removed the release day delivery option for non-Prime customers, so I can't use that anymore. I'll just be shelling out the extra $8 to get it on release day. I don't want to have to wait for it via 3-5 standard shipping, only saves me about three bucks anyway.
Not having the discount applied doesn't bother me either, just thought I'd post the Newegg deal. I'm keeping my pre-order with Amazon because of the $15 credit and no sales tax. I too will keep shopping with Amazon, nothing but great experiences for me.