I have been using Mack Heating & Cooling for a number of years with no problems. I have a yearly service contract with them. Alone with servicing my unit twice a year, they installed new air duct insulation, added a new vent in my den, and just yesterday installed a split-type air conditioner in the room over my garage. All of their service men are great to work with, but I started off with Kenny Ouzts, and always make sure that he is the one to service my unit or do any new installations. He is punctual, friendly, very knowledgeable, and just a nice guy to work with. Kim is also great to work with on financial end. She is friendly and patient with me and my different situations. They are just great people to work with, and does a great job keeping my unit serviced.