If you have DSL, never upgrade to FIOS. First, they won't let you go back if you aren't happy with it. So if you don't like a 65% increase in non-contract prices and paying $45 for batteries that go out once a year..... too bad. Don't fall for the bundle prices with all of the hidden fees - you will have a major increase in price going from a land line to Fios.
And once they get you, you can't even get the simple non-contract services & prices they would offer to someone should they move into your house. Ask someone at Verizon for some clarity on what prices they charge - it keeps changing based on who you are and never works out for repeat customers. Just go on-line, ask for a price quote as someone moving into your current residence, and you'll be shocked.
Verizon doesn't care at all about retaining customers just locking them into higher priced services (that offer negligible benefits over the prior service).
And if you really want to upgrade to Fios internet - avoid the TV at all costs. Installation will try to install old equipment, support will spend hours telling you how you can fix it on your own, and billing will tell you to pay for services incorrectly installed. And to top it off, the controls and features are flat out completely behind what others provide.
Good luck!