Great customer service from mail order would be Cabela's( always replaced anything I bought from them if I had a problem with it.)
For the local shops I would have to rate Salmon bay Tackle as the best customer service with Patricks fly shop running in 2nd.

For manufacture returns and service, I would say Ross and Shimano are awesome. Also I know others are not happy with G.Loomis and their new warrenty but I never had any problems and everthing was always taken care of right away.