they will be a very good team, no doubt about that, but his decision could'nt have been just based on how good the team he is going to would be. If it was, SF is the no brainer decision with that offense (on paper) and the great defense. I think he chose Den over SF cause of Elway.
I think it was this team was the best of the teams that would allow him to do what ever he wants with the Offense.