I think Siver has a decent chance of beating the odds and to shock the world. Obviously, McGregor is a huge favorite and has shown some impressive performances lately but Siver's fight versus Cub Swanson, who is my opinion better than Conor, was very competitive till the 3rd round. When Swanson was spinning a back-kick, Siver catched it and took Swanson down for nearly the rest of the round. I'd really like to see a similiar scenario in this fight as McGregor's a guy who loves these spinning techniques, too. That's being said, it's Siver's only chance to win this fight. Mcgregor is the better stand-up fighter, although his defense is in need of little improvement, while Siver's stand-up looks sloppier than McGregor's. Whereby Siver has some serious power and McGregor has been hit in every of his UFC-fights, so Siver has, despite McGregor's good chin, a puncher's chance.
Siver's key to victory is his ground game which is drastically underrated. This guy has improved unbelievably radical over the years. I'd say, despite what the UFC is trying to communicate, that Siver is more a better grappler than he is a stand-up fighter. I highly doubt that McGregor would be able to sweep him like he did against Brandao.
So, McGregor's a 3-1 favorite for me and it's absolutely ludicrous that he is a 7-1 favorite over Siver. Dillashaw beating Barao for example was a much huger upset for me, than Siver beating McGregor would be.
That's being said, I think that McGregor wins via TKO in round 3 but never count Siver out!