16 bucks a month seems well worth it. The cleaning process itself stays the same whether I have insurance or not. I've also used it at dentists and specialists who don't accept it. I pay up front and the insurance company reimburses me.
The catch is that most plans only cover 1k of work a year. It's very easy to max out if you need a couple of fillings or a root canal and a crown. I try to time things, if I can, so I get the root canal in one year and the crown the next.