Slow might be an understatement.  Regardless, there's really no sign now he'll ever come up to speed, and his background doesn't show any evidence of NFL style play.  He's a project with a lot of risk.

Sloter?  He looks much, much closer to the NFL style quarterback, he shows arm strength (more so than Siemian), accuracy, very good decision making, and protects the ball.  He looks much less the project than Lynch, and he even looks like he can step in for Siemian and maybe win a game.  Lynch shows none of that.  Heck, if Lynch was a mid-2nd rounder (like he really should've been), we wouldn't even be having this discussion.