Just to be clear, you have Verizon FIOS(FTTP) available in your area but you use Cox cable(HFC) internet? If so, that should be a easy choice to make. Fiber has faster upload, less latency, no bandwidth cap(at least with FIOS) and is generally more dependable, specially during storms. Part of the reason Cox is upgrading some areas to FTTP. It is just a better technology. Even if you weren't having problems with Cox, I would suggest switching. However if we are talking about Verizon DSL or cellular, that is a different story and DON'T suggest switching.