A factor to consider is the distance between the devices on the network. Copper (TX) has a limit of 100M (328 feet) while fiber can transmit at longer distances. Multi-mode fiber can transmit up to 2Km at 100Mbps, up to 1,000m at 1Gbps, and 550m at 10Gbps. Single-mode can transmit at a much longer distance with some samples transmitting at 10Km, 40Km and even 80Km and beyond.
It is always a good idea to incorporate a mixture of copper and multimode fiber ports in the switch selection so that if there is a need to connect to a device beyond 2km, the port available on the switch. Always buy a switch with a few spare ports if possible – it is less expensive than buying another switch for 1 or 2 ports.
For SFP transceiver specifications, click on the following link.