Not sure of the value of upgrading really. I am told to do it for security reasons. I upgraded to 2.8 from 2.7.1 a couple days ago and had so many issues I went back to 2.7.1. That is a hassle as I must redo my side bar all over again and lost some work, though not all because the text is backed up.
The big problem I had was when I would do a slight amount of editing on a post I stood the risk or losing the entire post's content. Images and all. I could of course restore the post by going back to saved revisions but if I reedited I was back where I started. Also issues with things like Lighbox2 and Ajax were not resolved in this release.
I am simply venting here after a couple days hard work, but I assume upgrade means to move forward, to get better. I bought into all the hype about 2.8 but I am back to 2.7.1 for major issues.
I hope other people have better luck than I did