When adding fiber connectivity to a network, I believe choosing the SFP transceiver should be based on more than the speed that is advertised.
Before selecting an optic, I usually check the switch or router compatibility first. The device must support the type of SFP or SFP+ module that is being considered, and both ends of the connection must work with the selected optics.
Fiber type is another thing to think about. Mode and multimode fiber are made for different situations, so the distance and the current cabling should be checked before choosing the transceiver.
I also look at the data rate that is needed, the transmission distance, the connector type, the wavelength, and whether the optic is right for the network equipment that is being used.
For example, picking a 10 Gbps SFP+ module does not automatically make a connection faster if the switches, cabling, or other parts of the link are limited to a speed.
Compatibility is also important when a network uses equipment from companies. Checking the details before buying can help prevent issues when installing the equipment.
While looking at fiber and network equipment, I have been using wavonline (http://www.wavonline.com/) to look at SFP, fiber, switch, and connectivity options and see how they fit into different network setups.
For people who work with fiber networks, what do you check first when you are choosing an SFP transceiver?
Is compatibility, fiber type, distance, speed, or support from the vendor the most important thing in your projects?