Just to give the other side...
I was really hoping the K271s would end my closed cans hunt (after hearing the wonderful K501s and K240Ss). You know not suffering from the V6's highs, PX200s lack of clarity, etc.... but after purchasing a used pair I sold them in a day. Unless there was something wrong with my pair, I can't recommend them for anyone. Muffled. Dull. Instrument placement poor. No top end. Overall near MDR-V250 sound (or PX200 or Triports). Shockingly bad. Very disappointed. I really don't think they did anything right, except isolate reasonably well and look nice. Even AKG
doesn't recommend them for "Hi-Fi" use and I can really understand why.
Anyway that was my experience for those considering a pair.