I usually like only using natural light, but sometime artificial can enhance an indoor shot. While this shot is not bad if it had artificial light it would look much better. The natural light hits most objects in the frame and the shadows are not brought out.
Flash and Natural Light
I believe for this shot using both natural and flash is the best choice. The natural light highlights the room with a yellowish light, but with the artificial light it changes that yucky yellow to a nice light white. This make it the best out of the three.
This is my least favorite shot. It looks way to artificial and the lack of natural light makes the photo look very bland. Out of the three photos this was my least favorite.
Thoughts on lighting
Lighting is very important to a shot; It can change the shot completely. Flash can be helpful in a dark environment, but it can make the photo look dull and not interesting. If you want to have a good photo I would suggest that multiple photos shot with different lighting. That being Flash, Natural, and a mixture of both.