Artificial photography lighting has advantages over outdoor or natural lighting in that you can control the intensity and angle of the light, but some pictures still turn out better with natural light. It might be a matter of preference or the desire of a client or subject for that matter. Natural lighting is often enhanced with a flash in an outdoor setting. When you choose your lighting, look for the best lighting situation to enhance your subject and make your picture as natural as possible.
For additional tips on photography lighting, check out this book by Evan Deveraux called “Photography Lighting: Ultimate Guide To Home Studio Photography Lighting!”