We used DB Waterworks because my neighbor was friends with the owner. I would say that we were not satisfied and would probably not recommend them. I'm sure they will do an okay job, but I felt that the owner used an inexperienced roof cleaner and charged a lot of money. We were told that our cedar shakes couldn't be cleaned properly and that our roof would need to be replaced for $12,000 in about two years. I have since had other roof cleaners give me different opinions.