Ill make it simple for you. Is a year of flight/medical benefits and starting the clock on your vacation time worth 5 grand?? If it is then do it. If not, then don't.
You sign a contract that has a buy out which is pro rated so once you hit 1500 if you want to go somewhere else use the bonus the other company give you to pay it off. You aren't locked into going to Envoy. Is that the smartest move? Is it ethical? Its up for you to decide.