I'm going to come at you from a metal head's perspective. With that in mind, metal uses a lot of distortion, so if you start playing a bunch of chords that have, say, four notes in them, you're going to get a cluttered mash of ass. Triads can pull it off, but not all the time. 7th chords and up just sound like total crap. That's why the power chord works so well. You're playing through a dirty signal, so it's best not to use too many notes and the power chord only has two notes. However, if you play through a clean channel and hit a power chord, you get kind of an empty sound. It just kinda sounds empty and incomplete. Namely because it's missing that 3rd. The lack of the 3rd helps the 5th add more power to the root with distortion, but just sounds emotionless without distortion. So as far as opinions go, mine says that distortion and power chords are a perfect match, but in the clean world it's a handle with care thing. Nobody will really know what kind of emotion you're trying to convey if you use too many of them in a clean channel.