Altima offers both month to month as well as pre-pay for a year (with this option you pay for 11 months and get 1 month free). When speaking with the rep they mentioned that if you ever decide to cancel mid year, they just pro-rate the amount you have left and refund it to you. There are no cancellation fees whatsoever. I also like that with the current deal, there is no activation fee (they only charge you $9.99 for a shipping/handling fee), the modem AND router rental fees are also waived for as long as you are with them.
Obviously I have no idea what service is like yet so I will re-post again later on!