Browsing a well organized file structure is perfectly supported by MPD. With clients available for virtually every device (ranging from purely text based clients like mpc or ncmpcpp to graphical clients) MPD is a very popular choice and the standard player of many manufacturers (Sonore, Bryston, Aurender, …) and audiophile Linux distributions. With upmpdcli as a front end and with a UPnP server running on the same machine that runs MPD, one has both options available: browse via a UPnP control point (if the metadata are good enough to support this) or browse the file structure via an MPD client (if the metadata do not allow a good UPnP browsing experience or the UPnP server does not support file browsing). That works very well for me, although these days I hardly access my music collection via MPD clients. This scheme also does not require transferring files over the LAN or over the wireless at replay time: just run upmpdcli (and hence MPD) and MinimServer on a RPi (mac mini, NUC, etc.) that also hosts your music file and the job is done. Control is via UPnP control points of MPD clients on mobile phones, tablets, laptops, etc.
With a distribution like GenTooPlayer and about 40$ for a RPi4, one can test this approach very easily. Just switch on MPD, MinimServer and upmpdcli in the settings of GenTooPlayer, open an MPD client or a UPnP control point on a mobile phone and let the music flow!
I use MinimServer since years. Installation and setup are very straightforward (on RPi devices, I never tried it on Qnap or Synology devices) and one can select which tags are indexed (and, perhaps more importantly, which are not) very easily. If you try MinimServer, make sure that you also install MinimWatch on a laptop or on a desktop computer. This allows you to start/stop/rescan/setup MinimServer very easily through a small graphical interface.
I use both Asset and Minim. I have a lot of classical for which Minim offers features which Asset doesn’t. Also Asset has stopped working with the Lightning DS app I often use to control the streamer in my main system. OTOH Minim doesn’t offer the “recent albums” feature which Asset does. Hence why I use two servers.
I subscribe to Minim2 and adding “recent albums” is on the future plans list for the developer Simon Nash. If this comes to pass I may well stop using Asset.
I use the full version of Asset. There’s nothing I need that it can’t do. I also run Minimserver on another NAS. I prefer the presentation of Minimserver, but would happily live with either.
When I started streaming I used Twonky on a Qnap. Reading this forum led me to dbpoweramp and Asset. Now Roon meets my needs, but if it falls over I have Minim on my Audiostore music server. I also use LMS2UPnP as a way of delivering the Roon experience across my Unitiqutes, but it falls short with HiRes.
When I had my NDS, I found my QNAP NAS running Asset with BubbleUPnP sounded better than my UnitiServe with its ‘proprietary’ UPnP. Asset with the LUMIN or Linn Kazoo remote app was also more flexible than the Naim app. Asset also transcoded Flac to WAV on the fly.
However, wierdly, when I switched to a ND555, I found the UnitiServe sounded better than the QNAP as a music server. So now I use my UnitiServe as my server/ripper, which of course transcodes Flac to WAV (all my rips are saved as Flac files on the UnitiServe and QNAP) and my QNAP is purely for back-up.