I'd argue they're actually much better than some bargain-bin realtek cards, especially if you want raw performance.

They'll also probably work out of the box on whatever "server" distro you throw at them, which seems to be an issue with the machine in question.

However, GP was most likely talking about actual NUCs, not NICs. I mean, there wasn't a typo. The point probably being that the CPUs in some of those mini boxen are likely to be woefully undercooled, so performance may not be what you expect by just looking at the CPU model.