I Couchsurfed during a conference in St Louis. It went very well. I would recommend a place that sounds quiet and has a private bedroom (vs. sleeping on someone's couch). It was also important, in retrospect, to be somewhat close to the conference location - as I ended up needing rides at the inconvenience of my colleagues. Both couch surfing and hotel life are nice at conferences - the former means that, after you present and you want a beer, you'll have people your own age to celebrate with, and hotel life is better for being well rested and preparing for your presentation the morning of. It's a toss up.