being host has both advantages and disadvantages in this game and in Black ops. This is where real lag comp falls into play. Before Black ops, MW2,waw and MW1. being host meant you held the lobby in your hands and everything in the game was dependent on you. While much of this still holds true. The new adjustments to lag compensation since Black ops will give you many times a disadvantage. it will give the worst connection in the room a fighting chance against you. I am not going to get into the science of it, but this is the main reason why you do bad when you are host.

As for how to tell you are host.Once you are in a lobby and a quick check with the back button will either show you as the only one connected to the game or if you have full 4 green bars and everyone else is orange at the start.

As for me i have good internet but rarely pull host for some reason. When i am host i can see the difference right away. For good or bad. Most times it is good because the party i play with are spread out over long distances. So we get a higher ping search and keeps lag comp to a minimum.