I have gone to the RSNA twice during residency. It is the biggest medical meeting in the world. I loved it and was totally awed both times. What you get out of it is determined by why you went there in the first place. What do you want from going there? It has a huge educational and CME lecture component, an educational poster component, a research presentations component, a research poster component, hands-on-courses component, a medical informatics component, a large trade show with the latest toys and technology, and multiple social events too. So, what do you want from the meeting?
P.S. You can also goof around and have fun in Chicago too, though the first week of December is probably not the optimal time for that. By the way, you misspelled RSNA.