First of all, I should say that Matthew and Knowshon are the only ones that can make this decision, and I wouldn't fault either of them either way. I truly believe they will both be successful on Sundays, and I will instantly be a fan of whatever teams they join. They are both Damn Good Dawgs, and I'll always be a fan either way. The other thing I should point out is that I truly believe their decisions share some common factors; however, the most important aspects are specific to their individual situations.
Stafford - He is projected by some as the number 1 overall pick. That is a HUGE accomplishment and honor, not to mention it would likely bring with it something in the neighborhood of 5 or 6 years, $70-80 million and around $30 million guaranteed. He could easily afford more frequent haircuts with that kind of paper. I could never fault a guy for seeing that opportunity and jumping at it. But here's the thing about Stafford: He's a junior quarterback. Underclassmen haven't had success in recent history: Alex Smith, Leaf, Vick, Vince Young, Akili Smith and Jamarcus Russell are either total busts or guys who had glimpses but now seem to have faded quickly. I'm not suggesting that Stafford won't be an NFL success if I he comes out early (Ben Roethlisberger has proved it can be done) and would be if he waited (having four years didn't seem to help Leinart, Leftwich, Grossman, Carr, etc). I'm just saying the percentages for success greatly favor exhausting college eligibility for quarterbacks. The other thing about Stafford is that (whether fair or not) quarterbacks are often judged just as much by their team's success as their individual accomplishments and statistics. Stafford's winning percentage as a starting QB for Georgia is good (26-7, 79%), but the problem is that he has never played December football (not counting the 2006 Chick-fil-A bowl). He's had very talented teams at UGA, yet has never won the SEC East, much less the SEC or national championships. My personal opinion is that Stafford should stay in school another year, where he can further improve his winning percentage, take another shot at a championship and enjoy greatly odds for success as the top pick in the 2010 draft.
Moreno - The main points for Moreno are a little different. Underclassmen's NFL success, as a general rule, is not much different from senior backs. In fact, being a first round lock with only 2 years of college football is actually a better thing for Moreno. There is no doubt that Moreno is a great back with all the tools NFL teams are looking for (even if he doesn't run a 4.3). I always hear that the average career for a running back in the NFL is around 3 years. This is largely due to the incredible amount of physical abuse the position takes. It's easy to surmise that each additional year of college football Moreno plays, could be 1 less year he will be able to play professionally (where I don't think that necessarily applies to quarterbacks). If he signs a 4 year contract as a rookie, he will want to be in the prime not twilight of his career when it's time to ink that second (and usually most lucrative) contract of his career. The fan in me desperately wants Moreno to return, and I will, no doubt, be ecstatic if he chooses to live another year as a celebrity in Athens. However, if I were giving impartial advice, I would tell him to work on his degree on the offseason and go ahead and get his money now. And buy that grandmother of his a nice new house.
Of course the other issue that I've conveniently ignored is the proposed rookie salary cap. This is certainly an issue to consider, as it could significantly impact their salaries. To me, this is more of a pressing concern for Moreno than Stafford. Again, looking at historical trends, running backs don't last very long so second contracts aren't something to count on. On the other hand, quarterbacks tend to take a couple years to adjust to the league (unless you're Matt Ryan), so they may just be hitting their stride when it's time to sign a new big money deal. The other thing about this is that it is still only hypothetical, and, from what I understand, only has about a 50-50 chance of being enacted.
So there it is. An admittedly biased fan's opinion that Matthew Stafford should postpone NFL millions, but (and this is painful to type) Moreno should not risk injury and should go ahead and get his paycheck.