I've decided I'm out.
I spent $61 for the game. If this were five years ago where you got pennies on the dollar for a trade-in like this I might feel more compelled to hold on to it and try to find a way to have some fun with it. Between the $20 promo credit and the $33.75 trade-in credit though, I'll cut my losses and consider myself fortunate to be out less than $8 on this thing. With all that credit, I can order Skyrim for less than $8 additional out of my pocket.
At this point, I don't know how much I'd really be able to play anyway. I'm enjoying FIFA much more than this. Between that, Skyrim next month, and the fact that my PS3 is hooked up to our main TV which I have to occasionally share with my wife, it's just not going to be worth trying to carve out the time.