What Price Glory was one of the great plays of the Roaring Twenties, a shuddering look back at the greatest war in history and people's determination not to go through that again. People actually took time away from their partying to go look at this one. It was one of the biggest hits that the Shubert organization ever produced, running 435 performances in the 1924-25 season on Broadway. And it was a popular choice for little theater companies to stage for the next 30 years or so. If you remember in the film It's A Wonderful World, James Stewart and Claudette Colbert find themselves in such a revival production at a company in the Hudson Valley.
What Laurence Stallings and Maxwell Anderson wrote got to the silent big screen for Fox Films in 1926 and it was deservedly a box office hit. Unlike The Big Parade it's Broadway success brought a built in audience to the movie theaters.
The male buddy film may well have originated with this film as Victor McLaglen and Edmund Lowe as Captain Flagg and Sergeant Quirt gave such powerful performances. Later on Warner Brothers by teaming James Cagney and Pat O'Brien teamed them in a variety of films and situations whereas McLaglen and Lowe only played variations of Flagg and Quirt when they weren't using those names. You can make a case for either McLaglen/Lowe or Cagney/O'Brien for inventing the genre.
One thing that is important is that like The Virginian which novel and play set the standard for western characters, What Price Glory did so for the male buddy film. These were not stock characters then, this is the original.
I'd be hard pressed to pick out whether The Big Parade or What Price Glory did the battle scenes best, capturing the horror of total war that the First World War was. In terms of plot I'd say What Price Glory has it over The Big Parade as a story. The two Marines McLaglen and Lowe are friendly rivals over women or liquor, but fierce fighting companions in combat. The object of their affection is Charmaine played by Dolores Del Rio, the comely innkeeper's daughter. Charmaine has her own song, one of the earliest written for a film of the same name that was a big seller in The Roaring Twenties. That also contributed mightily to the box office for What Price Glory.
The First Marine Division was the first American troops to actually see combat in France. These two and their fellow Marines might well be part of the Belleau Wood operations where Marines were rushed into bolster French and British troops when the German offensive threatened to break through.
What Price Glory holds up magnificently from the silent era, still as a reminder of the futility of war and the plucky comradeship that can develop from that shared experience.