There are those that believe the internal Manic Moose interface (or rather MPD) sound superior to streamed from Roon. I believe that is a load of cobblers. To my ear it is exactly the same, but YMMV.
When I was running The Roon core on a Mac Mini over Wifi MPD did sound better even on my little Pi. Roon soundstage was pancake flat. But when I moved the Roon Core to an SGC ST i5 and racked it alongside the pi and hardwired it with a quality ethernet cable thats when things changed. Now Roon sounds just as good as the MPD.