I was very happy with the experience I had with D&D.

I had them install 10 new double pane windows and one new sliding glass door leading out to a deck.
Their price was very good, they showed up on time, the quality of the materials was topnotch and they got it all done in less than a single day! I don't think that last item is standard, though - originally they had scheduled a day and a half but they sent 3 guys out instead of 2 so it happened more quickly than planned.

Everything was cleaned up afterwards, you couldn't tell they had been there except for the beautiful new windows.

I would definitely use them again and recommend them to friends.