Summary: The Head-Direct RE1 is a perfect example of a very special earphone that caters only to devoted audiophiles that have need for great sound quality. The special driver design that allows them to scale so well is both a pro and a con. It is a con in the sense that you need to carry around a portable amplifier when you are on the move, but a pro if you factor in the spectacular sound performance these in-ears offer.
Pros: Sound quality, Scaling properties, Very revealing, Balanced sound signature, Good definition throughout the spectrum, Smooth bass and treble extension, Incredible forward and airy mids for an IEM, Punchy and tight bass, that is incredibly precise, Good fit, Durable
Cons: Pricey, You need a good amp to make them sound their best, The need for an amp makes using them on the move more of a hassle