I found this tidbit on the QHYCCD Forums, i think there were some questions about what it will talk to enable the Pro firmware once it becomes available for the early bird customers. For most amateurs, the use of a single fiber channel would be enough. I think trying to use a bonded fiber channel (x2) unless you have permanent setup with a Tower/Server (not a laptop) probably wont be practical. Though if you have a newer laptop with enough USB 3/Thunderbolt ports, you could use Two thunderbolt fiber ports. But it does sound like it shouldn't cost much (if anything) to have the fiber ports enabled.
The QHY600U3 has only USB3.0 interface. The QHY600U3G20 has both USB3.0 interface and the high speed filber interface. And also QHY600U3G20 has rich external io which can used for advanced functions. The most important thing is that the QHY600U3G20's internal FPGA can be customized as the specially request by user (have extra cost or no cost, depend on how complex the project it is) . Which is very flexible for the research work.
The early bird price USD5000. using the QHY600U3G20 hardware design. So in future it accept to upgrade to the QHY600U3G20 version by patch the cost.