The knowledge of the salesperson and his willingness to explain what I needed (or what he recommended) to do. He wasn't trying to upsell me on items I did not need in my situation like the other company did. The no pressure sales tactic is always nice as well. The guys that did the installation were very professional, polite, and very informative letting me know on what they were doing. I'm hoping the same crew can come out in the Spring to finish up (installing the Turtle and vent covers). They really took pride in their work and I very much appreciated that.