Actually in my case my current farrier found me.
I tried 2 (both recommended to me) and trim was bad ( I did study books and videos so it's not a blank statement). So I run into this guy when I was taking a lesson, and he said right away toes are very long (and it was just 2 weeks after the last trim). Since I was completely agree and was thinking about changing to someone else I asked him to do the trim right there. So far he's trimming my horses for almost 2 years.
So the bottom line the references are the great thing, but often people don't even know what the good/bad trim and/or shoeing is. So I'd still go with the references, but also do some research on trimming and such, and if you don't like what the farrier does - switch to the next one.