From the Model Mayhem FAQ:
What is VIP and Premium and why do I hear so much about it?
Model Mayhem accounts are free to use, but we also offer an upgrade/subscription service that gives a boost to the basic features available on the site. There are different levels of upgrades at different price points: Premium will get you a substantial bit more than a basic membership but VIP is the best you can get.
You can see all of the features and options between the various subscription levels here: www.modelmayhem.com/upgrade
Here’s a small sampling of benefits: