We bought a house that previously had a roof look, and knew there was some mold in the attic. When we had that cleaned up the mold people told us that there was _still_ a leak. We called Tom and he was there the next day and discovered that the shingles were barely hold end by anything - just a little bit of of glue and/or nails at the top, but the bottom 4/5ths could essentially flap in the wind. He took a couple of videos to show it just how bad it was - no wonder we had water in the attic!
Tom gave our roof what we called a "tune-up", and fixed it up enough to make it through the winter. This was done by glueing it down in many places, add some nails in others (with caulking on top of it), and doing additional caulking around the flashing and other places. He also advised us that despite the fact that the roof was recently done, that it was done so poorly and with cheap materials that we should do it again next year.
Tom was extremely friendly and handled breaking the news of how bad it was to me well. He didn't try to skirt around it, and showing pictures/videos of the problems was a really nice touch. I'd recommend him to anybody.