We have lived in our 1900s-era home for 16 years now, and whenever we need roofing done, we call Harry Mercer. Harry Mercer Contractors is family-run, but with a large enough crew to do a job quickly and reliably.
Sixteen years ago they replaced our flat roof (which is still in good shape now), and this month we had them replace a slanted shingle roof (our house has several roof surfaces -- some flat, some slanted).
They also did the estimate quickly, and emailed it to us. The estimate listed the various steps involved, the materials, the cost, and their warranty period. I would definitely hire them again, although now that all our roof surfaces are in good shape, it may be quite some time before we'll need them again.