I preordered my copies from two different places: X from GAME (Online, I'll make it up to my local shop by buying the guide book from them) and Y from Amazon.
In the past Amazon always delivers on release date for me, though I always get their release date guarantee which is free. GAME is a bit more shakey, I have had games before release, on the release day and shortly after release from them... I'm hoping for an early release from GAME, as I'm out all of the 12th- Though my parents can sign for my copy, so if a copy arrives early I can play it on the train to London! (I've not got my hopes up though, I'm already prepared for an all nighter on the 12th to make up the lost time!)