This thing is a fucking beast. Obviously drives IEMs easily, but also delivers reasonably well as a portable amp/player for my HD6XXs. I get that a desktop amp is much better suited for the HD6XX, but the fact this thing drives them while I can wander around/lay on the couch instead of sit at the desktop is great.
I hate the search function and how barebones the filesystem is. It uses the old T9 text typing instead of a full QWERTY keyboard due to the small size of the screen. Sometimes this sucks ass, because you're waiting for a character to tick over because your search string has letters on the same 'key'. When you search for an artist, albums of that artist won't show up under albums, or when you click on an artist from your search, you immediately go to ALL their songs listed alphabetically, as opposed to a directory of their albums. Maybe there's a way of optimizing the search better, but I haven't found it. When you have ~13,000 songs on the device, it can be cumbersome. Manual navigation through the filesystem is easy, though.
But in terms of sound, it's awesome. Having both a 2.5mm balanced for my iBasso IT03 really brings out warmth and detail, and using high-gain mode with the 6XX is great.
There's a normal equalizer, and a 'descriptive' one that's actually really interesting to mess with.
The physical buttons for volume, track navigation, play/pause click well, and it charges by USB-C (really quickly) which a lot of yesteryear's best DAPs still didn't have.
You're not going to find anything else with these features at this price point. It's going to be missing 24/32-bit support (Not that 32-bit audio matters yet), or it's going to be missing the balanced jack, or it's going to lack the newest codecs, or it's going to cost a lot. If you care about UI, shell out the money for a Sony or an A&K, or wait for whatever Fiio comes out with this year. Otherwise, if you just want a lot of storage and really good sound, it's a good buy.