With only one month left, the early termination fee should only be around $60. However, make sure you are certain on your contract's end date. If you are looking at the upgrade date for a new phone, not that they often make upgrades available up to 6 months prior to the end of the contract, to entice you to stay.
Sprint has great coverage near interstates/large cities. Otherwise, it sucks. AT&T has the best 3G network in the country... Verizon Wireless has the best coverage, but bad customer service. If you live in a T-Mobile market, they also have GREAT coverage and very good pricing on monthly service.