Ive ordered 3 games from amazon pre order, all of them have arrived on release day. I wouldnt worry about it.
While I never ordered electronics from Amazon, I HAVE purchased other stuff (pre-ordered a couple too), usually books, graphic novels, and artbooks and a DVD
from Amazon.
Amazon usually ships and deliver things on a timely manner, sometimes even a little bit earlier than expected. ^_^
Just wanted to add some reassurance. It may not pertain to games, but I have pre-ordered stuff before from Amazon and had very little problems with Amazon.
(The reason I'm not buying Brink from Amazon is because I want Spec-Ops stuff, lol.)