In case someone does come along, I did use JumpRope at ROADS. Their support team was always helpful and responsive to our requests for features that fit our needs. Of the three Mastery-based grade books we used, JumpRope was by far the best.
One of their drawbacks is their reporting functionality at the school-wide level, although the teacher/student reports were more robust. We had to manually pull and create school reports for our leadership teams. I believe this is something JumpRope is working on for the future.