The Bryston music player server is MPD. There has been a long debate on differences in SQ between MPD and roon so you are not alone. But there should be a consensus by now on optimum configuration with roon, maybe on a Bryston community site.
That Bryston Pi is also actually a Raspbery Pi in a Bryston case. It has a much better power supply etc. etc. than typical DIY builds and should exceed the performance of DIY Rasberry Pi’s that many here have found success with but not by much. This guy is controversial in some quarters but it’s all explained here. Might be worth trying a S/PDIF input on the Wadia if you are using USB at the moment.