I have the K270 Playback now for a couple of weeks, and I really like them. 
Certainly better than the K271,and a lot of other closed headphones. 
Great AKG mids, and the treble, bass and soundstage aren't bad either. 
Comfort can be a issue though. The either clamp too much when you have a big head, or they are too loose when you have a small head.  
I had to remove the elastics in order to get rid of the tight fit on my big head. 
 
I bought mine on a Dutch tradingsite for 40 Euro, which is 50 USD. Plus new earpads. Well worth the costs.