It's really a lot more about air flow, pressure, drum speed, environment, etc., than source of heat. Depends what you're roasting with too. Is it an electric/gas air roaster or a drum roaster?
In other words, if you can re-create a roasting environment completely it shouldn't really matter where the heat is coming from or what is generating it as long as it is the same in terms of transfer and all other things are equal.