The Big Ten might have a 3-2 record right now, but the wins have all been quite impressive - Ohio State, Wisconsin, and Penn State all won against ranked and favored opponents by massively outgaining them and controlling tempo with tough D.
For the losses, Northwestern almost pulled it out today, again as an underdog. Minnesota's loss to Iowa State isn't a huge negative to me in a matchup between two 6-6 teams.
For the remaining games, I have no idea what to expect from the Alamo Bowl, given Michigan State's suspensions and Texas Tech's coaching situation. I do like how Iowa's defense matches up with Georgia Tech, particularly after seeing how Miami played GT earlier this season, when Miami just got whipped at the line of scrimmage by a much bigger and more physical Wisconsin team.
Anyway, those 3 Big Ten wins so far were all matchups between ranked teams. To date, it's got to be the most impressive performance by any of the major conferences.