One of our network architecture guys at work got it, had a bunch of problems with it (both the internet and TV), canceled it after a month of service calls where nobody could figure anything out, and is now going through Verizon billing hell.
I will say that FiOS is new to our area, so maybe they're still learning.
FiOS must really have Cox Cable scared because they've gone from having just one residential plan to now having many (including one that starts at $15, but I'd imagine that's to compete with DSL, not FiOS), most of which have SpeedBurst, which allows you to temporarily exceed your speed cap during a download, provided the network has some unused bandwidth available.
I'm happy with Cox Cable, but if they ever start pulling some of the stuff Comcast does, I'm definitely switching to FiOS. Thank god for competition.