While I find most RJs at private radio stations not playing their natural self, some being plain awful, including the best in the business- Mir of Radio Mirchi, there is one refreshingly different- Riddhi of Big FM. He's absolutely natural on air (and off it too, having encountered him in events) and connects well with his audience. No wonder his show 'Masti Ki Pathsala' is quite popular.
In events I've seen him do fillers between items where he mimics his office colleagues (not fellow RJs), sometimes they being present/ called on-stage, while the audience is in splits. A quality entertianer indeed.