Pros: price, sound quality, build quality
Cons: ok design, the 558 and 598 look much better
Sound stage is average, but separation is awesome. Some people clam that bass is lacking, however, I think the sound signature is absolutely great.
Sounds good even when driven by laptop and phones. This headphone uses the same driver as 558 and 598 but the outer shell and ear pads aren’t as good, that is the only down side. But you can't expect too much for $80.
Edit: after 1 year of use i replaced the cushions with the 558 one (555/595), more confortable, and i have pop out the grill and replace it with a piece of very thin cloth.. so lightly modded, sounds bit more airy, if you still planning to get one of the 5 series should really jut buy the 598, pretty cheap now.. though now i prefer brighter headphones like grado 325. but I'd keep the 518 forever