From the Model Mayhem FAQ:

What do the advanced Premium and VIP options mean?
As mentioned in when upgrading and in our membership level update thread we discuss several advanced options. This FAQ describes in more detail what those mean!

Advanced Profile Links and Images: The ability to use certain BB code in your profile!

Advanced Privacy Settings: The ability to utilize custom privacy options in your image albums, such as password-protecting albums or limiting albums to friends on Model Mayhem.

Top of Search Results Page: Premium and VIP members appear on top of basic members in Browse!

Casting and Travel Alerts: Get notified when a casting or alert that meets your requirements gets posted by others.

Multi-Location Search Exposure: VIP members can list up to 3 locations on their profile.

Ad-Free Profile Page: VIP members have the option to turn off ads via their settings.