Peter Kramer/AP

The Devil Wears Prada and so did Anna Wintour to the premiere of “The September Issue” last night at the Museum of Modern Art in New York, but according to designers and family alike at the premiere, that’s where the similarities end. As Wintour was joined by Renee Zellweger, Sienna Miller (who appears in the documentary as the cover girl for the titular September 2007 issue), Carolina Hererra, Oscar de la Renta, Donna Karan and more fashion glitterati, friends and relatives described Wintour as anything but a Devil. “She’s an amazing mother, an absolutely incredible mother,” says Wintour’s equally-stylish daughter Bee Schaffer. “She came to all my sports games. Her kids are the most important thing to her.” But that doesn’t mean that Mom doesn’t offer unsolicited fashion advice, like what to wear on a date. “She told me to change” for a recent night out, Shaffer revealed — although she stuck to the original outfit. And Wintour doesn’t just give advice to her children. Designer Zac Posen recalls Wintour once “asked me to take a sleeve off of a dress” early in his career. “I refused,” said Posen. “And a common respect level was brought to the table. And then the dress was later shot on Debra Messing.” Designer Marc Jacobs also described a formidable Wintour with a heart. “She’s smart and she surrounds herself with the most talented people. And she’s a risk-taker unafraid of taking chances. She doesn’t suck up,” he said. “And she’s been very good to me on a personal level as well. When I was having some personal problems, Anna was always there for me. She’s really a great editor. And she’s a good mother. She’s very maternal and caring to people she cares about. Anna’s really quite a warm person, who maybe has a different reputation. But in real life she’s very warm. . . and generous.” And while director R.J. Cutler received “extensive notes,” from Wintour, the editor tells PEOPLE “He ignored every single one. It’s his movie . . . his vision.” And does Wintour, who has seen the film twice approve? “I think it’s a wonderful document, on the amazing hard work, the creativity, the talent, the heartaches and the success.” The September Issue opens in N.Y.C on August 28 and nationwide on September 11. — Jeffrey Slonim