There's no indication on Whirlpool threads when there is new content (unless you remember how far down the list it was when you looked last), and clicking on a thread doesn't take you to the new content, I have to start on the last page and go backwards until I see a comment I recognise.
I was just thinking a few minutes ago how being able to reply to comments partway down a thread (instead of at the end with a quote) makes it easier to see the context of a discussion, but, makes it slightly unwieldy to find the new content (since it isn't just all at the end). I wished there was a button to take me to the next new comment instead of scrolling down looking out for those little orange indicators —- then I realised there actually WAS such a button! Amazing!!!
I also never worked out how to quote people on Whirlpool, but, on OZB, the UI is so easy to understand I never had such a problem. I could start using it immediately without having to work anything out.
TL;DR OZB rules
I only ever go on wp when it appears in Google search results.