i use it for my mini-z battery for almost two year usually one or two charge a day .so far no problem to my battery .and it take about 1 hour to charge 8 AAA battery.
the only thing is the first battery on the left will be 1.52v and the rest of the 7 AAA battery will be 1.36v after charge. but it haven't kill any of my battery yet. so i will keep using it.