Pros: Highs, Mids, transparency
Cons: weak impact, can sound 'thin'
I really enjoyed the RE0 for a while, but the sound was lacking bass. This happened if it was not driven properly out of the uDac or any other amp. Straight out of the iPod, there was something 'off' and it wasn't natural. The RE0 doesn't go particularly low.
On the other hand, the highs are excellent. So are the mids.
For the current price, they are a must-have.