The good old Radar Contact V4 can be downloaded for free so you can have a realistic ATC software for P3D and FSX !
The accurate phraseology, pilots requests to the ATC about the flight level / altitude change, following SID/STAR procedures, ATC chatter recordings, AI Traffic compatible.. Radar Contact V4 have plenty of advanced features to enjoy if you want a better ATC than the default one included with the simulator.
