risk and return dices on a financial paper

A risk vs return analysis of my p2p lending portfolio

In the past year I’ve tried out almost 30 European p2p lending platforms. In broad lines, the all follow the same business model: I lend money through them and I get paid interest, and they get a fee. But how do I rank them? If I was to make a top 10, I know which platforms would get into that list. I know Mintos would be my top 1 platform, but why is that?