I recently bought the cheapest Astell & Kern portable music player, at a price of $340 from Amazon. The only way to charge the unit out of the box is through USB to PC. That's weird, so I bought it from a seller that also included a wall and car charger, which are required for my lifestyle. It has 64 GB of built in memory and is advertised to play WAV, APE, FLAC and a few other formats. Naturally, I dumped a large amount of APE files onto the unit, since I still have them. And they didn't play.
That's no big deal, since I have a large amount of albums encoded in WAV. I always make cue files, so I'm using CueTools to convert the albums to FLAC. Through an accident, a JPG cover art got transferred over, and it automatically displayed while the music was playing. I prefer that over the stock images on the player and I'm adding the front cover art to each album. I'm estimating that I'll fill the player up at around 190 albums in FLAC. It supports one SD card up to 200GB, so I'm good.
The interface is clunky beyond explanation, so I won't explain it.
No headphones were included and I chose a wired pair by Focal, somewhat randomly. The Focal headphones are of course not quite as good as the Sennheisers I own, but they are also $450 cheaper.
This unit has bluetooth and I've never tried that connectivity before. It sounds pretty good when paired with my Audioengine HD6 speakers, which have a built-in bluetooth antenna.