In all likelihood BF3 will take best shooter, it should definitely blow CoD out of the water. I just don't know if it'll be able to beat ME3, considering it's the conclusion to a critically acclaimed trilogy. I can definitely see where you're coming from though and knowing my track record with predicting these things you'll probably be right...
Well, you have a good point in it being a trilogy ender. Means that all the big wrap up cutscenes and character "emotional bonding" will be going on...so it should be very close. I just haven't seen anything on ME3 yet, what I have seen though is this:
http://www.ea.com/battlefield3
And the seeing, is pretty. lol
Now don't think I don't have my hopes up about brink though. I really have hopes that Brink will snap developers out of this stagnet CoD FPS phase we've been in for the past 2 or 3 years. The FPS needs to change and Brink and BF3 are about to do it.