What models do Create ML and Turi Create use
TuriCreate has several different models implemented. You can either use them specifically or you can use a create method which will analyze your data and pick one of them (not always the same one).

For instance in binary classification (not image) there is support for random forest, decision tree, boosted trees, logistic regression, SVMs and nearest neighbor.

I don't know exactly how it makes the selection, but I imagine it has a lot to do with the dimensions of your data.