First to invent vs. first to file is largely a red herring. It sounds unfair until you figure out how the system actually works, rather than how the three-word

First to invent vs. first to file is largely a red herring. It sounds unfair until you figure out how the system actually works, rather than how the three-word phrase suggests it might work. First to file comes with a restriction that anything described in a publicly-available "publication" is not eligible for patent protection by anyone other than the author (who has the standard one year grace period, etc., to file). At the same time it eliminates a cause of controversy that only affects a small number of cases, but which can be exceedingly expensive to resolve. It replaces it with a very simple test: was there a "publication" describing your invention that was dated before your priority date? Go home. Reducing litigation costs is a good thing. This is also the way most of the rest of the world works. Life may be a little harder for the guy who invents something and doesn't tell anyone about it, but in theory the goal of the patent system is to encourage the publication of ideas.