Every person--your acting teachers, friends, agents, casting directors--will probably have an opinion about which makes for better actor headshots, and they're just that: opinions. The casting director for your favorite TV you're trying to get in the room for might have one opinion, while the CD for a film your perfect for might have the opposite opinion. At the end of the day, both indoor headshots and outdoor headshots have benefits. Outdoors can give us great natural light and variety; indoors can give us a more private and controlled environment. Listen to your gut about what speaks to you and your marketing plan.