Essentially telemarketers, they don't seem to accept in-bound calls at all. They used compressed air, blasted the ducts for a while, then used a weak vacuum to clean out the crud. On site, the tech offered to clean the furnace for $130 more and we agreed. Again, more compressed air blasting, and they left. A few hours later the house was cold and we realized the furnace was not working. We called and left many desperate messages for 2 (winter!) days and got no answer, then promises to send someone, then no-show. I had to call Direct Energy and pay $400 to rectify the (simple and sloppy) problem. Later I sucked up tons of crud in the ducts with my shop vac.
These guys are incompetent and dishonest. Reputable duct cleaning is not much more expensive than the $110 we paid, so pay the difference up-front, not in repairs later.