> It isn't clear to me but is the author indicating that Linux kernel support for 2.5GbE is still early stages, would it be better to wait a while before getting a motherboard with 2.5?

If you want to play it safe, waiting longer before buying new hardware is always a good strategy. As I wrote, though, aside from needing a new firmware package, I did not notice any issues with the 2.5G support in the end.

> There's a diff being presented between two lshw outputs? How is that diff shown?

I ran lshw > lshw-intel-285k-asrock.txt when I used the ASRock board and lshw > lshw-intel-285k-asus.txt when I used the ASUS board. Then I ran diff -u lshw-intel-285k-asrock.txt lshw-intel-285k-asus.txt and copy&pasted (parts of) the output into the blog post.