When FIOS was just about in our area, they distributed a channel listing and complete pricing list, so a group of us sat down with the pricing from Optimum (Cablevision) and FIOS (Verizon) and compared the two head to head.
In our case the channel listings were virtually identical.
(only difference is FIOS had BBC America)
Internet speed for FIOS was about 10% faster on paper but if speed was critical, Optimum offered a Boost service that doubled the speed, but for comparison we didn't include the boost.
We each figured out the cost based on the number of sets we each have, what channels we have, whether they are HD, any DVRs, etc...
Some were cheaper on FIOS and some cheaper on Optimum (including me).
Most of us converted to the one that was the cheapest for us and we have all had about the same level of service. Both pretty stable and both with relatively poor customer service (a sign of the times

).
We have since even run some speed tests and eventhough FIOS is about 10% faster on paper... we didn't see much difference, and each fluctuated enough that it is hard to say one is actually faster than the other.
One vendor was cheaper is you use more HD sets, or more DVRs, or one was even cheaper if you had a basic channel lineup but it swings to the other as you added more channels...
So there is no one definitive answer... if I were you, I would come up with a list of what you need and price it out for both options and pick what is best for you.
One note... we all saved money by getting the discounts of having all three services from one provider.
As far as technical comparisons, they are both VoIP so if you switch over your voice services, neither will keep the phone up during a power failure. Either get a UPS/battery or keep your cellphone charged. They are both fiber to the pole outside your house and they are both copper from your PC/TV/Phone to the interface box in your home. The stretch of cable from the pole to the interface box in the house is fiber under FIOS and copper coax from Optimum... not much difference.
Hope it helped... Good Luck
Pete