Bay Roofing replaced the roof on my previous home (which we sold last year). There was one layer of roof tiles up already, so we were hoping to only have to add a layer on top. After checking it out they informed us that the roof was too damaged and they'd have to remove it completely and start from scratch. We weren't thrilled with this news but they quoted us a reasonable price and another company who bid told us the same thing. They did the new roof quickly and efficiently.
However, they didn't notice that the house was missing flashing from an overhang all the way around, which caused leaking a few months later during heavy rains. At first we thought the roof had been done improperly but it turned out flashing was missing from another area. The contractor we got in to fix the problem told us it wasn't the roofers' fault, that they wouldn't necessarily have looked at the overhang, but in my opinion they were up on ladders and it was such an obvious omission that they should have noticed it, even if they didn't cause the problem. However, once we added the flashing we had no further problems, so I can't fault them for the job they did on the roof.