ESPN Insider article, so beware. If you don't have the paywall access, here is the final conclusion:
Tannehill wasn't able to win the Aggies' starting job in 2008 and was only moved back into that role two a half years later when Jerrod Johnson's injuries and erratic play left the Texas A&M coaches with little choice.
By contrast, Weeden came into a program that had a record-setting starter in Zac Robinson, so he had to wait until Robinson graduated to get a shot at the job. Once he received that opportunity, Weeden won the gig and dominated from day one, breaking Robinson's marks and winning all-conference honors.
This leads to an obvious question. If Tannehill had trouble winning over his collegiate coaches less than two years ago and his play since that time has been inconsistent at best and Weeden's path has been pretty much the exact opposite, why are people banking on Tannehill as the better prospect?
A five-year age edge is certainly significant, but when the entirety of the evidence is taken into account, Weeden is by far the better quarterback prospect.