Prompt and polite. Knowledgeable and on time. They took pictures before and after each vent to 'prove' how bad things were before, and good after. Excellent idea!! It was a normal duct cleaning - they cut a hole in your furnace ductwork (don't worry - its necessary and they fix it later with airtight tape) and hook up the super-powerful vacuume. The truck is loud, so if you have close neighbors or kids sleeping, I'd recommend scheduling around that. Then they go around to each vent and cold air return with compressed air and a few tools (like some sort of air-whip) to stir up the dirt/dust/etc. and the huge hose hooked up at the furnace sucks everything out to the truck. Once all ductwork upstairs is cleaned, they drill small holes in each branch off the main supply line in the basement and clean those just like they did for the registers upstairs. Then they clean the main. The only complaint I have was that there were some metal shavings in my carpet from when he drilled the holes in the supply branches in the basement (I have a finished basement). I wish they would have put a canvas dropcloth down or something to protect my carpet. On an up note, the guy found mold in my furnace since my condo had been vacant for a few months. He had the mold mitigation stuff on his truck and treated everything right then and there. All around a good experience.