For me, if I have a 3oC and a Fireteam Medallion on at the same time, I'll get purples for days. If I have just the 3oC, I'll get an exotic almost every 45 mins to an hour. Not sure if that's intended or if the medallion buff will take precedent over gear drops but that's how it's been working for me. Also, I've gotten an exotic from Mercury patrols and from a Lost Sector. Just FYI.