I bought the Pono player based on recommendations of Gavin, who knows about the technical aspects a lot more than me. He could may be add if he has time. I use Tidal on my Iphone as the main music source. I connect the Iphone via the lightning output to my DAC and AMP. Tidal streams in HIFI format, which is claimed to be FLAC. One can download music to the phone and listen offline. Tidal has all music that I was searching for so far. However, the drawback is that all your music becomes inaccessible if your Tidal membership expires. So you have everything but nothing.
The Pono is very simple. When plugged in to the computer it shows the Pono player and the SD card source. The loading of music is just copy and paste, not elaborate like Itunes. It can read mp3's FLAC and DSD formats. I tried DSD, it does work. It doesn't have wifi, bluetooth, nor digital output to an external DAC. It does have a balanced amp output and only high end DAP's have this option. The touch screen is ok. The sound is bright, slightly better than the Iphone. It has the highly rated ESS 9018 DAC chip. It comes with 128 gig memory. I think that if anybody has lots of downloaded music, mp3's, flac's, the Pono is ideal. It's just matter of drag and drop and there it is. Plus the fact of higher music quality in balanced output mode makes it a good deal, I think