That little warrantee customer satisfaction survey means more to the service manager than you may think. I haven't filled mine out yet because my warrantee brake work has not been completed to my satisfaction and they know it. However, I remember reading a thread about someone who blasted a dealership and now that dealer won't allow him back on the property nor will they service his X. Of course Nissan North America won't get involved. My take is just be honest. Let them know how you feel but in a professional manner. I would keep a copy with your receipt for your records just in case.
T