While JMP makes it possible to manage phone numbers without being tied to a major telco, the killer feature is being able to place and receive calls from a desktop or laptop. Texting from a full keyboard relieves me of a major pain point: tapping out characters one at a time on a virtual keyboard no a tiny screen.
I have been using JMP for more than a year. Now that the service is exiting beta, I am ready to cut my ties with my current wireless provider. JMP is the best phone service ever.