If you're about to do a radio interview, and the reporter or show host gives you a choice of doing it over the phone or in the radio studio, it's so choose the latter. It's always better to be interviewed face to face with the reporter. You develop a better rapport and the whole thing flows more smoothly. It also means that you can take calls if it's appropriate, but if you can't make it, don't worry. Just make sure you're prepared.