Understanding what you're trying to accomplish is critical.
For data network purposes (traditional L2/L3 switching/routing), 10G is typically the fastest current deployments are at without LAGs (port bonding/channeling for some vendors). There are some 40G deployments and possibly some 100G deployments out there, but these are expected to run over copper as well as fiber.
Now what we begin to discuss is distance. Fibre can send light farther than copper can send electricity (without regeneration). This means you can send the same speeds the same distances (ultimately) but will need regeneration to do so with copper mediums.
Now we need to examine latency. Latency differences over distances that do not require regeneration for electrical mediums (copper) will be negligible at best if you can even see a difference. Nodes that regenerate electrical signals will increase latency. Therefore, over long distances, copper has higher latency than fiber. The speed at which a signal is sent over a medium is independent of the bandwidth utilized. Put another way, the speed of light is a constant and does not change because you increase the bandwidth being sent over the fiber.
So what is "faster"? Is it bandwidth or is it latency or is it both? If it is strictly bandwidth (the amount of bits which can be transmitted and/or received within a given interval), then for L2/L3 switching/routing fiber and copper are nearly identical or will soon be identical. If it is latency or bandwidth + latency, then fiber is "faster" but only once your distance exceeds the distance limitations of a single run of copper (which then requires regeneration which adds latency).
We can also add another factor to this: is "faster" any or both of the afore-mentioned (typical) measurements plus the ability to multiplex multiple bandwidth channels over a single physical medium? If this is the case, then fiber is the clear winner. It can multiplex 160x10Gbps signals over a single fiber. This means a single fiber can operate at 1.6Tbps. These must be MUX'd and DMUX'd, so this is only applicable in backhaul transport of the data and not in end-user/device implementations.