well, I know of some of the differences. Sound can reach a higher volume on the skinnier one, and there are some different colors, such as I have a true clear for my smaller version, not like the cloudy clear I've seen on the bigger one. and there is this blue clear and yellow clear I've seen for the skinnier one. so far, I've seen nothing to tell me the the bigger one is better, though, on my skinny one the sound is starting to fade, that could be the system or just my ear infection, i don't know. But if you have the choice, get the skinnier one. But don't drive yourself crazy looking for one, I only stumbled across mine.