How is Brickhouse's open mic?

I've played guitar and sang for about 30 years and have never played in front of anyone before. I'd like to start playing out in the new year. Is it pretty welcoming or can the crowd be kind of rough? Are the other performers usually regulars and are they easy to get along with? Are there certain styles of music that won't go over well or are inappropriate? For reference I was planning to play a few instrumental John Fahey tunes and sing a Bob Dylan song or two. Is there anything else I should know?