Just got back from the Tysons Corner MS store.
Traded in MK vs. DC Universe (red GH box), Guitar Hero III (had no barcode, marked not for resale), You're In the Movies (no barcode, marked not for resale), Blazblue Calamity Trigger, NHL 11. I got a $40 gift card with one of the $10 credits going toward Halo Master Chief Collection.
They took all of them without issue. The only problem was that the store was packed, there were several people trying to trade in games, and they started turning away people unless they made an appointment. Oh, and some people tried to trade in gen 6 games but they don't take those.