I am an owner of AKG K702 and previous owner of Shure SRH 840. Switched to AKG K702 ater my Shures broke and was blown away by the sound of K702s (very flat response, fantastic soundscape, fantastic soundscape, great for learning new stuff by ear). However, the K702s are open back, and I needed a closed-back alternative for several reasons. K271s were a good choice -- share the overall sound of the K702s, with a slightly stronger bass response, slightly harsher upper mids, slightly worse soundscape imho, but hey, for the price, they are excellent.
The build quality is OK, just feels somewhat cheap compared to the K702s -- the cables ale less flexible and the plastics and ear pads look cheap somehow. But they are very comfy to wear and lightweight, too -- unlike the SRH 840s, which very on the heavy side, and if I wore them for a longer time, my head was overheating. :) OTOH, the 840s were blocking the outside noise a tad better.