Like aaronwt said, AMC is not changing the way they send content. Most likely FIOS will be re-encoding the mpeg-2 feed on the fly. So FIOS will not be able to improve the quality but it will just let them save bandwidth for more channels/content. It would break too many things if the networks themselves switched to h.264 at the source. I'm sure some point in the future more networks will do that but I don't see it happening in the near future.