Couch Surfing can be really cool. I've stayed with two nice people and had a really great guest stay with me. But lately I've been getting 2-3 requests a week from backpackers wanting free accommodation. I wouldn't mind so much if they didn't just totally ignore me when I respond to their messages with information about how to get to my house and some ideas for things they might like in my local area. I put effort into responding to their requests and they never let me know whether or not they are going to turn up, leaving me keeping nights free for them and then discovering they don't bother.
Dear Couch Surfers - Have some courtesy to potential hosts. Tell us if you are not going to turn up.
Do I recommend it - yes, with caution.