Hey, headwax. I'd say Perfect Effects strength is being able to combine the different effects, adjusting each effect to get the look you're going for. I usually go through a few favorites and combine them for my overall look. Sometimes I have a stack of 10 or 12 layers before I finally hit apply. Even after that, I sometimes go back in with the completed images and run it through some of the filters again. I usually end up with 2 or 3 finished images that I like. The torture is decided which one is the one I'll use.

Another good thing is that when you get the look you're going for, you can save the whole set as a new filter, then you're able to apply that one new filter instead of having to go through the whole process each time.