By other MG:
“Other Magical Girls often categorize them as antisocial, quiet, loners, and unstable. There are a lot of rumors regarding Dark Magical Girls. Many have realized that Dark Magical Girls tend to have something troubling them, something that occasionally causes them to… snap. Combining Dark Magical Girls’ unpredictable personalities with the power they wield, many think they are simply ticking time bombs. Bombs that are uniquely capable of hurting other Magical Girls.” Selene ch.21
Examples of rumors:
“Dark Magical Girls are unstable. You can’t trust them. They only care about themselves. They’re crazy and will attack you without warning.” Selene ch.21
Rumors are mentioned to be worse among new MG as they only know what they have heard from other MG, leading them to be negatively predisposed to Darks.
Among older MG they are generally treated with caution. Though those who have interacted with Darks treat them more normally.
With jealousy given Darks starting bonus.
By non MG:
Rumors about Darks have been kept from the general public, so they are seen a just another type of MG. And are quite popular, due to their unique fighting capabilities, rarity, and more mysterious public personas.
Despite hearing the rumors from working in close proximity to other MG. Darks are Magical Soldiers and wardens second favorite type to work with after Blues, as they tend to have significantly less MCS, and are easier overall to work with.