The suprising success of He-Man with small boys prompted the creation of a similar show for young girls. While the toy line is naturally way more girly (focusing on hair and combs to brush them), the show was luckily not limited by these restrictions.
In a comparison to He-Man, many things stand out as improvements. Adora's origin of a princess stolen from her home and raised by her kidnappers to be a cruel military commander. The main villain, Hordak, is more imposing and was actually the teacher of the other show's villain Skeletor. She-Ra having abilities beyond stuff used for fighting, like healing and animal telepathy. Not to mention the awesome sword that could transform into almost anything.
The show is not without it's faults. Some of the more gimic abilities of She-Ra's allies are ridiculous (Castanetta throws nets). The one guy, Bo, struts like a manly-man while wearing a midriff top that only covers his chest. Teela (the similar but opposite gendered character from He-Man) could beat him silly. And while the show was geared more toward girls, it got a little silly with things like sleepovers.
While both shows followed similar formats and moral topics, She-Ra was allowed to explore things not allowed on He-Man, like romance and childbirth. These risks lead to a more superior product, often neglected because it is a "girly" spin-off of a popular boy's cartoon.