Whew.. so glad I found this plugin! My forum has very long-lived threads (sometimes years long, with couple of hundred pages each), so it is essential that the latest posts are on the top of the first page. I find it annoying that xenForo devs have in several places commented that they "don't see any point for such feature". Different use-cases have different needs. I know that if the reverse post sort order wasn't available on my board, it would die quickly.
This add on is very useful for us as we report live events and update frequently. Users don’t have to change pages to find out what is going on. Used with Sticky First Post makes this a great addition to our community.