Ahh the old student vs adult coach debate
Ultimately, do what works for YOUR team. And you may want to make some of decisions depending on your goals. If your goals are for the students to do and learn as much as possible, a student coach may be the way to go. If your goals are to learn from the past, have mentors & students work hand in hand and learn from eachother, maybe a mentor is a good idea.
1511 started with a student/adult pair that traded off, but since then has been fortunate enough to have very driven, interested & mature student coaches. Our team does a ton of strategy work in the background (which is done by both mentors & students) and has lots of scouting, and for the most part tends to lead strategy discussions with alliance partners. You need a very strong & intelligent student who knows the rules backwards and forwards in order to do this. If you have a student like that, I would say definitely go with the student. A mentor can be the backup in "tough" discussions with "pushy" adult coaches - believe me, we have encountered our share. In general at first glance, a lot of adult coaches won't give the same credibility to a student, BUT, the good ones will quickly recognize knowledge & talent. However, if your student coach can't control the drivers and can't hold their own in a strategy discussion, maybe its a good opportunity for an adult coach.
Ultimately, again, its what works for your team. I have seen student coaches that are far better than many mentor coaches, but I have also seen drivers that do much better having a mentor coach. Really, its all about WHO you put in that position and the skills they have, not how old they are. Your drive team needs to have chemistry and they need to be able to strategize & work with other teams. So just pick the right person for the job