So this can play FLAC files from an external USB HDD? And if you have everything organized in a bunch of sub folders, is navigation user-friendly and fast?
Also, anyone compare the sound to a Squeezebox Boom, which is the best portable wireless speaker I've heard?
I haven't compared it to a Squeezebox Boom, but regarding the play of USB HDD... specifically, via the Sonica App for iOS (I have no experience with the Android version), the app's navigation of the files on your USB stick or HDD is really nice. It parses through all the files - of any supported format - and presents them by Artist or Album or Song. I've even tried putting songs 14 subfolders deep, beneath the root level of the drive - and it finds them and displays them, no problem. In addition to the Artist, Album or Song lists that the Sonica App displays, it also allows you to manually navigate by Folder. And it offers a Search that allows you to put in any portion of a song title, artist name, or album and it returns every possible result - as a "contains" search. For example, Searching for "pa" will return a song titled "Be Patient", an album titled "Pause" and an artist called "Chappaqua," for example. Impressive - it makes searching so easy.
And if that were't an awesome enough UI - all controlled via WiFi from your mobile device - you can mark "Favorites" and play only Favorites, later, if you choose. Any one of the lists can be played straight through, shuffled, repeated, repeat album, repeat song, etc. It's really very nice - especially if you have any experience working with the spectacularly lousy UIs that we're used to seeing with many DAP manufacturers.
Add to that, the ability to stream Tidal from your iDevice or play songs stored on your iDevice, but the Sonica App's handling of USB-attached devices containing audio files is the best I've seen of any UI. (Again, I only have experience with the iOS version of the Sonica App, and by the way, only with a mix of 44.1/16, 44.1/24, 48/24, 88/24 and 96/24 kHz FLAC and WAV files.)