The HTC one m9 is the best for music because boom sound amplifiers Dolby Audio and the snapdragon 810 for immersive sound the a9 has not got the boom sound amplifiers or the 810 chip set it only has Dolby Audio no amplifiers for the headphones like the HTC ONE M9 its all about the music not for playing games on it a good way to kill your phones you have an Xbox or PlayStation for that and with the M9 new update 6.0 I can get about 60 to 70 hrs of hi end music playback with my 128gb micro SD card and my Sony XBA z5 headphones that is a hi end mixes up if I do say so my self in the music aspect it is a beast and you need to use power amp :)
HTC who were once making lovely phones are now dead n gone. it's really sad that a company like HTC who makes only phoned can't make just one decent good looking flagship anymore. my last one was One X and I am done with HTC for life.
Wtf is going on with HTC? It's so simple. Do a modern and updated design of the M8, put the fingerprint scanner on the back, keep the boom sound speakers on the front. Upgrade the cameras and keep the awesome battery life