Little known is probably that the device next to SMB / CIFS also supports the WebDAV protocol. This expands the range of app Alternatives immensely! WebDAV URL: 10.10.10.254/data.
I use the RAVPower FileHub but exclusively as mobile music server Music Mount. So that I can stream my music collection on a USB stick or disk for iPhone / iPad. Works very well! Instructions (with video), there's at musicmount.org.
I also have the Kingston MobileLite. The Kingston app's better, otherwise the RAVPower has for me but in the lead. Weaker battery, a mobile operating at Kingston MobileLite with hard drive is practically impossible. When RAVPower FileHub the battery lasts for connected hard drive (WD My Passport Ultra) at least for a good four hours of music with Music Mount. If the music stored on an SD card or USB stick, it will be a whopping 8-9 hours.