Of course they prefer the sun. It's their natural environment. As long as the heat and humidity are not too high, the sun will provide the best light. I'll go out on a limb and say that most grow indoors NOT because they prefer artificial light and prefer paying higher electric bills that arouse suspicion but because either they can't control the weather (snow, rain, hail), fear discovery or theft, or simply don't have the outside space. I take my plants out into natural sun every chance I get.