Absolutely the worst. Stay away. I manage properties here in Las Vegas and a few landlords have existing contracts with them. They have terrible service, rarely clean the machines, in one instance the laundry was down for 2 months and Dadson couldn't be reached by phone. In my experience they over estimate the revenue they will pay for placing machines and never seem to show up when you need them to.
When someone wants to leave Dadson, usually for disapointing service they are famous for sueing landlords to enforce their contracts. If you are considering these guys ask around first and check with the BBB, and google reviews.