Horde mode was introduced in Gears of War 2, and while it was a great addition, fans complained about it being poorly executed, lacking variety and simple features like host migration. Epic Games took your bitching feedback into consideration, because Horde 2.0 in Gears of War 3 is making a bold statement
Horde 2.0 looks to be more substantial and consistently keep players on their toes: you have fortifications to build, repair, upgrade and defend, on top of killing locusts and bosses to survive and earn cash at the same time; all without worrying about the host ending the game. The long desired host migration has finally been added in Horde 2.0. If the host decides to quit, the game will transition over to the next suitable player and you can invite someone else in to continue the onslaught.
I've seen it with my own eyes!