My mistake. Early draft (with incorrect information) included in the article. Our network guys corrected me. Here's what it's being updated to read:

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Finally, while 10Gbps Ethernet can run across standard Cat5/6 cable, we elected to use SFP+ connectors. We chose this to have the flexibility between optical (fiber) and copper connections. Some network card and switch vendors lock down their equipment to only support proprietary SFP+s, which they charge a significant premium for. We spent significant time testing a combination of SFP+ vendors before finding FiberStore, a SFP+ manufacturer from which we could directly source SFP+s at a reasonable price that worked in the network gear we wanted to use.

For anyone interested in copper vs fiber, take some time to read Chapter 1 of Nathan Farrington's dissertation: bnathanfarrington.com/papers/dissertation.pdf

As 10Gbps, and even 40G/100G, gain traction, you start running into cable length issues:

Attenuation and maximum length of AWG 7 copper wire:

Bit Rate (Gb/s), dB/m, Loss/m, Max length (m)

1, 0.721, 15.3%, 106

10, 2.28, 40.8%, 33.5

40, 4.56, 65.0%, 16

100, 7.21, 81.0%, 10.6

Thanks for the timely update.