This is one of the best fights that Joe Silva has put together in a good long while. Weidman is definitely the man right now, but with the controversy surrounding his wins over Anderson Silva, many people feel that he won't be truly validated as champion until he defeats Machida.
Machida immediately made waves once he dropped down to 185lbs with his first round head kick knockout over the always-game, Mark Munoz. This was after being a perennial Top 5 fighter in the 205lb division. Machida himself says that he feels better than he ever has, and it's shown in his fights with Munoz and Mousasi.
Who's going to win? It's hard to predict. On the one hand, you can't discount anyone who is undefeated with two wins over Anderson Silva, but on the other Machida is one of those fighters, with his Karate-based style, who many of his opponents have struggled to figure out. He really only has two real losses--his KO loss to Shogun, and his submission loss to Jon Jones. His losses to Phil Davis and Rampage Jackson were both poor decisions. What's more, is that Machida has beaten many people similar to Weidman.
Part of what makes this fight so intriguing is that it really is hard to predict a winner. If Weidman can take away Machida's speed by banging away at his legs, and/or turn it into a grappling match, he will win. If Machida can stay on the outside, and catch Weidman overextending, he'll win. Really it's going to come down to whoever can find and establish their range first. One thing is for sure though, UFC 175 is going to be a great night of fights.