I've had both in a few types of guitars, here are my generalizations : The Custom 5 will have a lot more bass than the Perpetual Burn, and despite being a little more powerful, it sounds a little cleaner than the Perpetual Burn, I'll guess because it has less mids. I like it, it's kind of just like the site says, a more powerful 59. The Perpetual Burn is probably what a lot of people wish their JB would sound like: Less high Mid Hump, tighter (albeit less ) bass, and a simply amazing ability to clean up with the volume control, really the best I've ever heard from a higher output type pickup, from full on distorted to chiming clean with plenty of treble and without that dull clank that the higher output types can get when played clean. Sorry, I got off on a little tangent there, but to summarize my experience: The Custom 5 is a bassier, more vintage type tone, and the Perpetual burn is a brighter, more modern tone with more mids (think JB, but less power and better manners).