The speed is good, but who needs more than 200 to 500 Mbit? My main gripe with fiber is that all devices like router, DVR and DECT phone need to be connected to the main fiber modem. If there is some problem with the modem, then it's game over, you will have no services. With cable, the modem and DVR work separately, and can both be plugged into the wall. Of course, the WIFI router and phone will still need to be plugged into the cable modem, that's why I call VOIP retarded. But the modem can be placed into a work or bedroom (next to the desktop), instead of the living room or technical area what is often the case with fiber modems.
I forgot to mention, that with fiber, your speed also goes down when watching TV, so 50 Mbps will become 30 Mbps depending on how many TV's are switched on. This doesn't happen with cable, you will always get full downloading speed. http://www.verizon.com/home/fios-fastest-internet/