FWB Pros and Cons

So there's this guy that I've known for a while. He doesn't want a relationship and has made it incredibly clear that that's not going to change. However, he has proposed the idea of a friends with benefits type of thing. We've hooked up once when I was drunk and from what I can remember things went pretty well! I'm wondering if anyone has an advice or inputs on these arrangements and if they ever end well for either parties. Thanks!