In my memory SQ, Columbia, was the first then Sansui put out QS which was heavily reputed to be the best, better format. If I remember right SQ being first had a lot to do with it being more popular and I'm sure something to do, later, with licensing and other issues, record labels committing to one format or the other. Sansui was generally considered the best with their QS system. There were a few outboard decoders considered very good if not better. Lafayette had one that was considered very good, some thought the best of the matrix devices.