I don't have FiOS TV, which apparently can be a major issue if you do, since some of their newer TV hardware REQUIRES the use of a FiOS router to retain full functionality of the boxes.
But without the TV piece, I just have my pfSense box connected to the Ethernet connection on my ONT. I didn't have to do anything fancy for it to work (WAN is set to DHCP), and have no issues getting nearly full speed out of my Gigabit connection. IPv6 is not yet available unless you're in one of the four (possibly five) areas that seem to be in their testing for it.
DSLReports is great for provider-specific setup questions.