Not only does Diesel make you pay for wifi, but it's as noisy as a nightclub. I left there with my head throbbing from the blasting Scandinavian death metal and the people having to shout over it, and this was at 1:00 PM on a Sunday afternoon. That was my first and only attempt to do actual work there (usually I only go in for take-out coffee or socializing), but that experience repulsed me enough that I'll never try to get work done there again. I'll try Panera, as you suggest.