I just had my ducts cleaned thoroughly last weekend by Royal Duct. I tried booking a couple of top reviewed companies but since they had no convenient times available, I went with a friend's recommendation and I was very happy. They came in on time, worked very cleanly. Even though they had a bit of trouble running their line through my small basement window and that took a bit of time, they didn't rush the job and they thoroughly cleaned the ducts running the airbrush several times until they were happy with the result.
They also didn't haggle trying to sell me odorizing or antibacterial sprays like other companies did in the past. Punctual, patient, thorough, I definitely recommend their services.