The biggest problem for me hasn&#x27;t been the battery but the sluggishness of iOS8 on a 4S. There are times when it simply won&#x27;t react to touch input anymore for a while. Some bugs have accumulated as well - my alarm clock won&#x27;t go off anymore (timer still always works, even over night, strangely enough), sound output is sometimes broken until I open up &quot;Music&quot; to sort of reinitialize it, the lockscreen is sometimes frozen etc. It&#x27;s been barely usable but I&#x27;ve held on. Sad there is no iPhone mini.