I would encourage you to watch them play.
As for scouting reports, the ones I read all focused on how Raekwon McMillan was one of the highest recruited Mike's out of high school, and how he was born to play the position. He was the brains of that Ohio State defense, organizing it and playing Mike exceptionally well. He is very instinctual at the position, and almost never makes a mis-step or mis-diagnosis. The kid is a Mike, pure and simple. Any report that cast him as a Sam, is probably off. Watching him play he is strong at the point of attack, a great tackler, and plays the run exceptionally well. He can also pass rush a little bit. So, I can see how someone might use him as a Sam … but this kids skills are pure Mike all the way.
As conscientious and hard working as McMillan is … I'm just not sold on Baker having those same hard working qualities. Baker is tremendously fast, and has the talent, despite being safety-sized. But … he is going to need to prove it to me by putting in the film study, mastering the playbook, and refining his game before I'm going to feel confident playing Baker too much. He still has a long way to go, IMHO.
The only thing that Baker has over McMillan is speed. McMillan is the more instinctual player, the better organizer, better tackler, better run defender, more mature, better prepared, more devoted to refining his craft, and more dependable player. I'd take McMillan over Baker 8 days a week. Now, I do hope that Baker adopts McMillan's work ethic, because Baker has a high ceiling. But, He hasn't really shown that he is devoted to reaching it yet. So, I need to see that.