I have used Beacon Plumbing a couple of times in the past. They are notoriously expensive but they have been reliable, dependable and quick -- and I don't mind paying a bit extra for that. They make a big deal out of telling you they charge by the job, not by the hour -- which is just a way for them to obscure the cost.
WIth my most recent experience, the quote was so ridiculously high that I sent the plumber packing. I am fairly well experienced with plumbing and knew exactly what needed to be done -- I just didn't have time to do it. They wanted $475 for 1 hours worth of work (his estimate of 1 hour, not mine).
There are many other quality plumbers in town that charge reasonable rates for routine plumbing; there is no need to use these thieves.