I don't think being in a landmark building means FIOS is not an option. It goes building by building, but I am pretty sure some landmarked buildings now have FIOS. Ours doesn't yet, but that's just because we could not get Verizon to act on our desire to get it. Last I heard there was a recent meeting with representatives from buildings in our complex that are interested in getting FIOS--but I need to follow up and find out what was said at the meeting. It was with a Verizon rep, I believe.
We got FIOS at Washington Plaza recently and I am very happy with it. The picture quality, the assortment of channels and the speed and reliabilty of the internet are better than Spectrum.
Verizon, though, is very unreliable about billing and following through on what the initial agreement called for. They even change the channels available with no refunds. You have to watch the bills for the first few months to make sure they are not over-billing. As the salesman said to me, "Everyone gets a different price." They also do not accept credit cards for discounted automatic billing. When I think of Verizon I think of unnecessary dishonesty. A great product with bad billing and customer service.
The fiber optic cable is smaller than Spectrum. It is less intrusive in the building. They used to have a large box that they would install in each apartment but not any longer. Now, you just get the 4k canister shaped modem-router.
The hold up for years here was that the management would not sign off on it. Once they did, it was installed fairly quickly. They sent in specialized teams to install each phase.