well... i think its better to work as a team, however the team has to be focused to work together with a common goal. the leader as to motivate them to work happily and cheerfully so as each individual is motivated to give 101% of themselves.
Depends on what I'm shooting, if I'm streetshooting, I prefer alone, because got some friends like to move fingers infront of the glass, or stand between you and the subject because they're bored. Lost a few images because of these fiends :sticktong
If weddings, also alone better, too many people very hard to make everybody happy.
If models, 1-3 is good, can interact and take time to shoot, else 20mins all same pose, ZZzzZZzzzzzZZZZZZ.
Sometimes I prefer to work alone when i need or feel the need to have the extra special connection with my photos or when i want to just take photos and reflect on them peacefully, by myself. It's my way of de-stressing sometimes.
Otherwise, I get a photo buddy to go on 'assigments' together so we can share tips and ideas on greater photo techincalities or opportunities!