I have had to call D&M on several occasions. Every time, they sent me friendly and knowledgable staff to help me with my problem. They are always on time, and don't make you wait forever when you need the help. One winter, my heater broke, it was only 35 degrees in my house and I have a little one at home. It was on a sunday when I called and within 20 minutes of getting off of the phone with them, someone was knocking on my door. Another 45 minutes after that, they had figured out what was wrong and fixed it for me. I didn't get way overcharged like you would expect from an emergency weekend call either. I have always been over satisfied with all of the work they have done.
PROS: fast, friendly, knowledgable, low priced