Glenn, Mike is correct. There is no way that any router has the actual HP they claim to have. One HP = 746 watts and that is the output watts, not the input watts. Since the standard 15 amp North American circuit is about 1800 watts then the most a router can be is about 2.4HP on the input side. Since routers are only about 65 to 75% efficient that means that you can only have about 1.75 HP on the output side where the work actually gets done.
However, since all the manufacturers are lying about their horsepower more or less equally, you can still use their claims to compare them to each other. As Mike said, the best way, in more absolute terms, to compare one router to another is by using the input power. An even better method is to compare output watts. That is how much power you actually have to work with.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.