I've had good luck with Harding Sails in Marion, MA. I've also heard good reviews for Squeteague Sailmakers in North Falmouth.
Harding cleaned and stored my sails one year and when I called to pick them up at the Marion Loft they assured me that they would be ready. I arrived to pick them up and discovered that they were still at the New Bedford location that they had at the time. OK, this was about 10:30-11 on a Saturday, they closed around Noon......... Well ,I was disappointed, but figured I could wait until next week. Graham Quinn (Owner of Harding) told me that since they had "goofed", he would personally be sure that my sails were DELIVERED to me that day! Sure enough, just after Noontime..... the other fellow (forgot his name?) that was working with Graham Quinn that morning drove up at the driveway of our cottage in Wareham (where my boat is stored) and delivered my sails! He had personally driven over to New Bedford to get my sails and then brought them to me, no extra charge!
If that is how they treat a Day Sailer owner who had them clean his OEM Neil Pride Sails......... I'm IMPRESSED!! Their canvas division made me a sailcover and, again I received top service.