For grilling, I've heard that eucalyptus is OK. However, for slow smoking I wouldn't recommend it because of its high oil content. I tried it once and the ribs I cooked tasted like they were basted with turpentine. The garbage disposal that is my neighbor's dog wouldn't even touch them.
Unlike propane, you'll never wake up scorched and naked in another county because you mishandled a bag of briquettes.