I was looking at the X550s myself, and thankfully found this thread.
It appears that most of the cards on Ebay are from Asia - does it mean all of them are fake? Is there any way I could tell a real one from a fake from the photos?
I suspect that most of the cards on Ebay discussed on this thread are cheap pirate clone cards, built in sophisticated factories in China and loaded with copied firmware. They might be functionally identical to the full priced retail cards, and they might never fail during the life of your hyper-converged file server. Or they might fail the first week. NIC cards and SATA storage cards like the IBM M1015 are commonly sold from China. Whether it matters to you, is up to you. For the price, you might be able to afford a primary and a back-up. Or pay full price from a retail vendor.
What about dell branded x550's? Would there be any reason to avoid these for Freenas? It looks physically identical to a Intel unlike the Chinese copy above, it also has the Intel logo on the pcb. Just curious if it has some custom firmware or something that will be a problem for using on non Dell hardware.
I have 2 "LSI's". they don't work. they are recognized themselves, but they don't see any drives connected. don't buy unless they are legit or you don't mind having decorative PCB's for your wall, these are pure garbage.