My experience with the apps on the multiple streamers that I have owned or had a chance to borrow has been:
1. Streamers OWNED for multiple years (Auralic Aries and Aries Mini): Auralic Lightning DS: very good; no complains
2. Streamer CURRENTLY OWNED (Eversolo DMP-A6): Eversolo app is at least as good as Auralic Lightning DS
3. Bluesound Node borrowed and used only as a streamer: App was generally better than the Auralic or Eversolo apps, but two bugs (Benchmark DAC compatibility via USB and album art size limitations at that time) caused me to return the product. Disappointing.
4. Wiim Ultra borrowed and used only as a streamer: App was unacceptable. 1. Cannot search across streaming and local (NAS) content (deal-breaker); 2. Album art on local content would not appear regardless of a number of attempts to change some relevant settings on my NAS. Note that both of these items work perfectly on the Eversolo and Auralic apps. Overall system response of the Wiim Ultra was much slower than the Eversolo and Auralic streamers, but this might be hardware related.
My verdict: The Eversolo app is the winner by a very small margin. The Auralic app is also very good. More or less a tie. Also, both apps are extremely stable.
I have never tried Roon, but the idea of having to run a separate to computer as a core is totally unappealing to me. My preference is to use a streamer with an app that does its best to not get in the way!