The folks at Reddit run a variety of surveys, and they recently put together an interesting one about uniform popularity. They asked respondents a pair of questions. One was a yes/no question, in which respondents were asked if they liked a team's jersey. The second question was to rate jerseys on a scale of 1-to-10. You can view the charts and raw data here.
The San Francisco 49ers ranked second on raw likability, and third on rivalry-corrected likability. The process involved averaging the yes and no votes, and then throwing out divisional votes. They found that divisional votes often were lower than other teams.