This discussion has been done before. My point of view which will stir a few things up, is that the EC120 is a proper single engine turbine, comfort, handling etc etc......
The R66 is still a Robbie bit bigger airframe, but with a little turbine in it, and not much space in the back, except for two people and a midget in the middle. Also this aircraft has not been flown around in the open market for along period of time, I reckon in the next few years there will be issues with vibration of a turbine in a robbie airframe.
But there will be lots of punters in the market place, that have part exchanged their R44 to get to fly a turbine aircraft, but this time will be able to fit the golf clubs in the back.
Remember people it still is a robbie with a turbine in it.
EC120 proper aircraft....... thats why it is a little bit more expensive.
Fluffy