Keller Chryst is going to have to be exponentially better than Jarret Guarantano to start imo. If it’s close, you have to go with JG. 3 years of eligibility with JG vs 1 with KC. You’re in trouble in 2019 if JG transfers. Chryst isn’t talented enough to pull it off.
Chryst is a solid back up option for if JG gets hurt. That's just how I am looking at it, and in my opinion is what the staff is thinking too.
I'm not worried about the QB race. These guys want to win right away, and won't let anything distract them from that goal. I bet both get some snaps at some point this season either way.
All things being equal or even with a senior being only marginally better, go with the young'un 110 times out of 100.