I wouldn't call my experience with Verizon FIOS incredibly bad, but perhaps very bad or dismal.
I had FIOS at my old house When went to cancel because I was moving, I was told not to cancel and to put the account on some type of temporary hold so it could be reactivated at my new place. The advantages of this as it was proposed to me was that I'd avoid any installation charges and get a $300 gift card from Amazon.
I move to my new place, call in, speak to a number of either very ill-informed or disinterested agents who make Comcast look like the Ritz Carlton, one of whom transfered me to and gave my personal information to some sort of telephone phishing scam called the "National Rewards Center" who's now calling me from India non-stop.
I finally reach a person who is puzzled that anyone would have told me what the first person told me and that there was no installation fee and I need to send back my equipment from the old account. I was also told I'd be getting my gift card after I activated.
Now, a few weeks later, I'm told I'm ineligable for the gift card because my charges were lowered from some arbitrary high number to a reasonable number that was proposed to me by the agent, and the agents who told me this were wrong.
When you shop this service against Comcast don't count on the $300 and don't believe anything anyone there tells you. If someone tries to transfer you to claim your reward, write down their name (his was "Marcus") and then throw the paper in the trash can because no one at verizon will know what to do with it.