We used Flynn Roofing and we were happy with their work and their professionalism.
We had Duffy come out and give us a quote. In our meeting, Duffy noted that they were more expensive than others but that was because they did a better job. Flynn was cheaper (don't remember by how much but it was considerable) and they were professional in installation and our meeting with them. I guess time will tell with the roof but it's been over a year and we haven't had any issues.
It's only been less than two months, but it seems to have worked out all right with Ipswich Roofing. I have no direct or indirect experience with anyone who's done a bad job, but some companies out there seem all over the place in terms of price.