I went from Cox Cable to Fios and have been kinda ho-hum on the deal. Fios works, but Cox worked also. The speed appears to be similar, and the service is similar. Same POS Scientific Atlanta (Cisco) boxes for tuning. A fair list of additional channels that I don't care about, and the rest look similar to what I had been using already.
On the plus side, they did a solid job installing their router in place of the old cable modem and installing their boxes in place of the Cox boxes. Should be straightforward, I realize, but I have a seriously integrated system, so wasn't sure the guy would pull it off cleanly... Was happy he came really close and it all worked fine after I spent about 10 minutes getting the cabling dead on.