[tor-relays] Qualities of a good relay (Sean Saito)

I’m currently working with Dr. Virgil Griffith on Roster, a tor project that aims to reward relay operators with good relays. Right now we are brainstorming how to measure/quantify a good relay. Besides the obvious requirements of a good relay (e.g. speed, geo-diversity, constant uptime), what qualities make a relay valuable to the Tor network and its users? Thanks, Sean