We are currently in the process of getting a new roof installed and so far we have had what we see as serious issues with this company (including water damage to the interior of our house and improper waterproofing / protection of unfinished roof areas that we had to point out to them).
The job is dragging on with only a 2 person crew and it sounds like everything else takes priority over getting the job done. Excuses offered include: employee personal issues, vacation, office Christmas parties. For a big company and given the time of year I can't fathom why additional staff haven't been made available and sent over to help or replace the crew when they're not available.
We've had to deal with an unfinished roof over the holidays, a bad leak due to improper installation of a component (goodbye workday), and our insurance company threatening to exclude our coverage because of how long the job is taking.
We also found out, after watching the installation process, that we were not getting the 2 inch insulation that was in our contract. Only once about half the roof was done and we asked 'hey, when is the insulation going in' did the roofing contact person tell us they didn't see a need to install it and that we'd get a discount on the quoted price because of this. The actual roofer had no clue insulation was even part of the original plan. You can decide for yourself what this might imply. To our further delight, the contact person also told us we'd be charged for extra material they had to use, but relented once we argued that should have been covered by the quote.
Given our poor experience so far I strongly recommend you choose a different company for your roof.