Contex has replaced the three sections of my roof and my front and back eavetroughs over the past two years. They are probably not the cheapest company out there, but after they did the first job they earned my trust enough to bring them back twice more. I did note an earlier poster's problem with delayed arrival times in the busier season, but I found that a few phone calls did the trick and they came to do the job soon enough. I had an issue with a small leak at one point, which they misdiagnosed at first but eventually found and repaired (it was coming from an old section of the roof). I found Phil a pleasure to deal with, and their workers were extremely diligent and tidy. Problems can arise with any job, but I would recommend them because they care about their reputation and want to keep their customers happy. My house is watertight.
When it's time to move to a new house, if I need a new roof I will call them first.