America has a number of shows that are second tier to the big 3 (K-1, Pride, and UFC), and King of the Cage is one of those. Actually, it might be a bit further down than 2nd tier which includes much larger venues like Superbrawl and Strike Force. King of the Cage has a lot more sloppy fighters, a lot more ref mistakes, and some pretty brutal KOs as a result of both. It also has money to attract one or two big names per PPV (generally fighting no-names) at the expense of everyone else earning anywhere from a couple hundred dollars to a few thousand for fighting.
Jackson is something of a free agent right now, as he and Pride are in a bit of a war--UFC execs have said, so far, they have no interest in signing him, so he is working pretty much anything and everything between dates in Japan (Jackson has also lost his last few fights, which is hurting him.).
As I said before, Pride is in some trouble, so we will see if it survives as one of the big dogs. Unfortunately, without it the Japan scene is a bit lifeless--the K-1 MMA shows are generally put together for freakshow entertainment as opposed to a more "scientific" approach that Pride embodies. Also, the yakuza are pretty much everywhere in kick-boxing, MMA, and wrestling in Japan, so there will be more fall-out coming soon.
http://youtube.com/watch?v=8MV61Ohfn2Q&search=pride%20fighting is a highlight video of the KOs in Pride (has few submissios, for some reason). A lot of big names appear in here including CroCop, Liddel, Silva, Don Frye, Bob Sapp, Ken Shamrock, Fedor, and Nogueira.
http://youtube.com/watch?v=IP1LNZPGsXI&search=fedor is a clip montage of Fedor Emelianenko--the Pride heavyweight champion. He is undefeated in Pride and is the single best puncher/ground and pounder (GNP) in the world of MMA.