Star Spangled isn't all that good. It is familiar which is why I feel people like it but its not the best crafted song. God Bless America is a much better hymn and gets more emotion out of its simplicity.
The Yankee Stadiun Dr who does God Bless America still always gives me chills:
God Bless America is so simple in what it is trying to get across. To simply love and protect your free land, and to never loose loyalty.
I don't know if there is a scienece behind a anthem but it should be grand but also simple. You should be able to perform it with a orchestra or just a solo person and it should still provoke some emotion. Many of the "newer" old colonial posts in Australia, Canada, the USA fall flat on this and have junky anthems. You find the best anthems in the old nations or in many of the fresh new ones.
Russia is the best by a mile and even the old Soviet anthem was good too.
You see when it is a well crafted song versus war propaganda peddled as a national hymm. Italy for example is a terrible song, it's battle music for the trooops not a anthem. When its played with a orchestra it sounds very cheesy with all the high notes in the song. France has this issue also but it is a better quality song then the Italian anthem but is war cry not a well crafted song for a anthem.
God save the Queen is another steller anthem and song. If a anthem is superior people will just sing it. My mother used to practice with that she her chior because it is a good song. Period. It serves all the points of being able to be stripped down or dressed up and the song gives you chills.
For many of the newer nations, many used the Brit anthem as a base to build there so for many African countries for instance you get quality anthems. Nigeria and South Africa come to mind off the top of my head. For South America Brazil has the best one that is the more authentic. It is a beautiful song but very festive and upbeat. You can't help but move around when you hear it.