They were remarkably professional and hard working. Bob and Elaine, the owners, stopped by the work site to check up several times and bring in supplies, etc. All work was done as promised, as far as I can tell to a very high standard. The worksite was left clean and neat, and the crew was a pleasure to have in my nouse. They even returned after I signed off on the project to make one minor modification, and they will return again to add a bit more refrigerant as the weather warms. Bob, the owner, showed me different options and equipment and clearly explained advantages/disadvantages of each. The company even personally paid the amount of a PG&E rebate that they had promised, even though it expired. It's really been great to deal with them, and the heating at least works great. Haven't needed the A/C yet, but I'm sure that it'll be fine. There are some regular followups planned to make sure that everything is functioning properly. Full disclosure: Bob and Elaine both have asked me to join Angie's List to rate the company, but they told me to be honest and objective. I wish that more small businesses were of the same caliber as Diamond. Enough butt kissing, okay?