It is rare to have a choice between contract or month-to-month service. Most internet service providers either don’t make contracts mandatory or require one which is either 1 or 2 years long.
With that said, most consumers prefer to stay on a month-to-month plan as there is no Early Termination Fee involved if the service is canceled earlier than the term of the contract. But, when you sign up for a contract you can often take advantage of a lower per month price. At the end of the day, it comes down to your personal preference for one or the other.