They normally work together, but they also work independantly. Which one do you like better and why.

What has Shellback done solo?

Max has given me tha slays by Pink

Max Martin > Max and Shellback. > Dr. Luke > Shellback

Max Martin

Obviously Max... He had 13 years of hits before taking Shellback under his wing. And he works more frequently and with a greater range of writers.

Best of Max-less Shellback:
Cher Lloyd "Want U Back"
Maroon 5 "Payphone"
Victoria Justice "Beggin' On Your Knees"
Carolina Liar "Salvation"
One Direction "Kiss You"