I have used 32 3oc in the last 24 hours and received 4 exotics, 2 290 and 2 310. I wouldn't say I love the drop rate, but that is still less than 10 strange coins per exotic, less than 20 per 310 exotic. I am mainly using them to infuse stuff, so I don't care which exotic I get, only which equipment slot it is in.