I think there is some deal about the new "forum spy" not being as robust as the old forum. I think they are working on tweaking this. As I never used it, I guess I don't know what I was missing.
Overall, my primary complaint is limits in the number of posts displayed on a page and the number of of threads listed in a forum index page. The magic number is 100.

It gives you a better look at recent posts without having to flip back through pages. I understand this is being worked on. I believe my other complaint, turning url images into attachments (without having to download the image to your computer first) is also being worked on.
Other than that, I find the new forum to be a great step forward. It's much easier to navigate around using an iPad. I use both an iPad and my MBP.