True, and valid concerns.
The answer is not straightforward, though. The shorter battery life, under specific usage/settings, is not a fault.
Like all modern devices, usage and settings make major differences to the battery life. For me, an iPhone lasts multiple days. Many other users cannot get even a full day of usage. There is great variability among users, and it is due to their different usage/settings. Would I like to see the iPhone be better? Of course. But it is what it is.
The Sony DAP, I usually use Direct mode, playing local music files from the SD card. I do not use Streaming at all on the Sony. So for me, battery life has never been a concern. In fact, the Sony has class leading battery life. I don't think there is another DAP that is even close to it.
Other users use Streaming a majority of the time, with DSP functions on all the time. Some like the display on all the time. These users will have a drastically shorter battery life.
So it depends on usage/settings......... Which is great, as the choice is up to the user.
Most DAPs have a run time of 8-12 hours max, reducing further from that with battery hungry applications.
The Calyx M I had was around 4 hours, which was a major reason for selling it. There were just too many times when I picked it up to use, and it was dead, or had a very low charge. Sound wise, it was better than anything else on the market.....
In hindsight, I regret selling it. Should have adjusted to using it with an external battery to supplement, or just kept it for use at home.
