Ask for the quote in writing with a detailed description of what will be provided and the cost, as well as payment terms. Contractor should also be able to provide a copy of his contractor license and a certificate of insurance along with references.
If you live in a state with heavy winter snow and part of driveway passes over sidewalk consider having that area treated for resistance to salt corrosion. Be careful yourself about use of ice removal chemicals. You will be very sorry if you then get scaling away of the surface.
What mix are they gonna use. Are they gonna use fiber mesh, if not what type of reinforcing steel will they use. Are they gonna saw cut for crack control or use expansion joints. How much base are they gonna put down. What kind of process ( base ) are they gonna use.