I would say that there are four main categories of Power Metal. This definition is home-made so don't laugh at it... :wink:
The thrashy Power with bands like Iced Earth and Morgana Lefay
The Flower Metal, represented by Freedom Call and Rhapsody
The Classic Power with roots in Heavy/Traditional Metal with Hammerfall and Helloween
and then there is another one which I don't know what to call but contains bands like
Blind Guardian, Falconer, Savage Circus and Kamelot.
I am listening to about 40 PM-bands so I'm not a true expert, but I base this opinion on that. And of course bands must not be entirely in one of these categories...
But the PM hate is interesting. Except those mentioned earlier Children of Bodom were shitting their pants a few months ago when they were called PM. I would say that the Metal Archives definition of them is quite accurate: Speed/Power Metal with harsh vocals.