Strengths and weaknesses are apparent in all the quarterbacks the Vikings had under contract this season. Bradford displayed historic accuracy last year and has a strong enough arm, but he has very limited mobility and is injury prone.
Keenum has much better mobility and was the guy to rally around this year. Would it be the same next year? It wasn't for Joe Kapp (I know, a million years ago), but maybe he's the right fit, given his low turnover rate (until yesterday) and ability to handle the blitz.
Pre-injury, Bridgewater looked pretty promising, but no one can say what the injury and two years of inactivity will have done to him. I'd hate to trust the QB position to him when the team has to think they are a Super Bowl contender next year.