One would think that it would be a good thing to have the same insurance company representing both parties because all of the facts of the case are known, and theoretically the process could move more quickly.
However, the fact the is that when the same insurance company is representing both parties within an accident case, the insurance company is going to be working in it's own best interest, not necessarily the best interest of it's clients.
When two insurance companies are fighting against one another, both are trying to win and get more money for their client. But, when the same insurance company is working for both clients, it can short change both parties because they are not facing pressure from an outside source.
Because of this, if you get into an accident and both or parties have the same insurance company, you may want to enlist the help of a personal injury attorney.