Just want to share my experience today
As one of those people who pre-ordered from dell, I couldnt wait anymore to play. So I went to BB and bought mario and sonic for $30 then traded it in at EB pacific center. (i think one guy got lucky with him having it for full value) The trade value of this game is actually $35. The guy was going to charge me more and then I asked him about the deal. He went to ask and then said its fine. So 29.99 + 9.99 + tax + hassle = 44.78 which is essentially the same as dells deal minus the hassle.
On a side note, after I got the game, I went to the dell chat and ask to cancel my order as they said that it will be shipped May 15 when I ordered it on Apr 11. The agent said that he will give me additional 10% off the price before tax which I agreed. So if this all works out in the end, I might return a copy to EB or sell one to my cousin who is in the same boat as me.
hope this helps for some of you who are in the same boat.