Sounds great, right? Well the sound is something you have to consider when using the power chord. Because the chord can be used as both Major and minor, the chord does not sound either Major or minor. For certain styles this is perfect because we are not interested in the quality of the chord, we just want something that has a strong sound. This is why these chords are used quite a bit in rock and metal styles.
You may notice that some of these shapes use 3 fingers, 2 fingers or 1 finger. This depends on the position of the chord (open pos. vs. moveable) or if you want to double the root note with your pinky.
When placing your power chords, you have to have a good idea of the mapping on the 5th and 6th string of the guitar. Here are the notes on those strings to help guide you when playing moveable chords.