My experience with preprints? The publication process at ThePeerJ was super fast (~ 3 months from submission to publication). In this 3 months 84 people visited the PrePrint and only 52 downloaded the PDF. Nobody commented on it. Taking into account that we are 11 authors (who should account for some of this downloads), you may think that the visibility of the paper didn’t increase much from being out there in advance, but I can prove you wrong. Maybe not much people read it, but I was contacted by one PhD student with a question about the paper. She was working on the topic and preparing the next filed season, so for her, reading it in January, instead of in April was useful. Plus, she found it by google-ing about the topic, proving that preprints are discoverable. So, not always by publishing preprints you reach more people, or get amazing feedback, but at least you can reach the right people, and that’s important enough for me.