Are you interested in surround sound? ARC is more advanced in this respect.

Is the TV mounted in a cabinet or on an open wall? Neither ARC or BEAM would be optimum if the TV is recessed in a shelving system, but BEAM would be somewhat more appropriate for this case.

hi, thanks for reply TV on open wall, arc would be mounted to maximise upward speakers (connected to existing tv mount). assume beam 2 more direct, same audio quality, just not surround experience.

“Best” sound is in the ear of the listener. The two units sound different to me. For surround, both units would require rear speakers. SUB adds a lot of fun for the chase scenes and will increase the midrange clarity by offloading bass from the main unit.