Peta Hunt, editor-at-large for You & Your Wedding magazine, said the gown, with its fitted bodice and full pleated skirt, had a 1950s feel.
“I thought it was fantastic. The gentle v-neck is caressing the shoulders,” Ms Hunt said.
“It’s got a slight 1950s couture look that helps massively to make it look different from Kate and Meghan’s wedding dresses.”
She added: “She’s worked with her shape. She has a fabulously long train and no veil. It actually shows off her face. It’s very sophisticated and elegant.”
Ms Hunt predicted Eugenie’s choice would inspire future brides.
“I think there will be girls following that trend,” she said.
Buckingham Palace said the low back feature on the soft white dress was at the specific request of Eugenie, who had surgery aged 12 to correct scoliosis and has scars on her back.
Eugenie’s sparkling tiara was the Greville Emerald Kokoshnik Tiara, lent to her by her grandmother the Queen.
The tiara was made by Boucheron for Mrs Greville in 1919 in the fashionable “kokoshnik” style popularised in the Russian Imperial Court.
The tiara is made of brilliant and rose cut diamonds pave set in platinum, with six emeralds on either side.
It was bequeathed by Mrs Greville to Queen Elizabeth in 1942.
Eugenie’s diamond and emerald drop ear-rings were a wedding gift from her groom Jack Brooksbank.
The Peter Pilotto brand is known for its innovative textile design, paired with a modern feminine silhouette.
The palace said the princess has been wearing designs by the brand for several years, and worked with them on the design.
On the dress are symbols of personal significance to Eugenie, including a thistle for Scotland acknowledging the couple’s fondness for Balmoral, a shamrock for Ireland as a nod to the bride’s Ferguson family, and the York Rose and ivy representing the couple’s home.
Pilotto and De Vos reinterpreted these symbols in a garland of rope-like motifs, woven into a jacquard of silk, cotton and viscose blend.
Eugenie, who once revealed she usually does her make-up in the car, had help for her big day.
Her hair was styled by Sonny-Jo MacFarlane of Hari’s, with make-up by Hannah Martin of Bobbi Brown.