Summary: I bought those primarily for my university year abroad. I simply couldn't imagine taking full-size studio cans like my K271 on the plane. As I liked my 271, I simply went for something from the same company.
In spite of a lot of negative comments, I have come to like them for what they do.
Pros: Small & collapsible, inexpensive, decent sound
Cons: Comfort and isolation lacking, sound is "only" decent