Honestly, I might be tainted because the first event I went to was a Pride event, but the Octagon gets in the way a lot. Especially the cameramen hanging over the edges. The ring was way better, from a spectator standpoint. I've been to many events (Strikeforce and UFC) and it just seems like the cage is great for branding and TV, but not so great for spectating (Although the high up seats actually a better angle than some of the "better seats".
Also be prepared for a lot of amped up, affliction shirt wearing bros.