Calling it the "iTunes of 3D printing" is going to have big problems for you. iTunes means different things to different people. Some love it, some hate it. So

Calling it the "iTunes of 3D printing" is going to have big problems for you. iTunes means different things to different people. Some love it, some hate it. Some see it as a marketplace, others see it as a way to store their music. iTunes is not an MVP or a starting point. Choose a better way to communicate your product.