The first thing I notice is that the OTO could stand to be improved, but that's not what you were asking about, so I'll listen on.
The levels are well balanced. Neither the vocals nor the instrumental overpower each other. However, the vocals are rather dry. Applying a slight bit of reverb should help glue the vocals to the same "space" that the instruments are in. The original song also seems to make heavy use of chorus. What program do you use for mixing, by the way?