If you have a true "fiber to home", then of course you will enjoy the high-quality speed options available... but as you have been told, most providers today have fiber to the main hub in an area / an appartment block and then use traditional cables to the end-points, which of course is cheating you about what they sell.
BUT... the speed does not only depend on the cables, but also on the hubs and servers... if they do not deliver the throughput that the cables could give you, if the serves are laid out to small and overloaded with the amount of data requested, then your service back home will still suck and be appalling.
