I used DNS for one year and when it worked with my work flow, it was awesome. It was $100 a month and auto-deducted from the company credit card. I wasn't using it enough at the time to make it worthwhile so it was a big decision to sign on for another year. You can't do month to month.
I had to get it through a 3rd party whose company only accepted the annual plan. I was wondering if there is only one way to purchase it or if others work with someone who allow month to month. It seems that after a year of paying on time, going to month to month would only be beneficial to them. They can turn it off whenever they wish especially the cloud version.