Have not owned a BeoMedia 1, but have a BeoSound 5/BeoMaster 5. The BeoMaster 5 is connected bot via HDMI, SPDIF and MasterLink.
Sound quality wise, it uses the SPDIF to transfer sound when playing via the TV (PC function). I have all my music in WMA lossless, so it sound very good.
My TV is a BeoVision 7-40 MkIV, so I guess the connection options does not compare to your BeoVision 5.
/MikaelB