See my review of Buck Jump for a more general description of the Dirty Dozen Brass Band (ddbb).
What's Going On is a "remake" of the Marvin Gaye record of the same name. I was a bit apprehensive whilst waiting for it to arrive, but I needn't have been: I was always a little bit uneasy with Gaye's album, as I felt that there was too much incongruity between the political/ecological content and its Soul style (whereas Let's Get It On was the perfect MG album for me). But DDBB's remake was motivated by Hurricane Katrina (which had important ecological and political ramifications), and they have made important changes, e.g. rap vocals in addition to the sometimes funkier sometimes jazzier style. I do like it more than the original. Track 9, a rap version of Inner City Blues (Make Me Wanna Holler) is also covered on Buck Jump in a more Mardi Gras style. Some of this style remains in What's Going On thanks to the sousaphone emphasising the bass line. All in all, I love it.