The problem for SS N7 is not the performance. The battery charging and exploding has become a real life issue. Supply has been stopped in some markets pending investigation.
http://english.yonhapnews.co.kr/search1/2603000000.html?cid=AEN20160831012100320
http://english.yonhapnews.co.kr/search1/2603000000.html?cid=AEN20160831012100320