I can't believe I'm saying this but...Posh.
The little details of the below the knee skirt length and towering stilettos gave Vicky that extra edge imo.
I'm not familiar with the singer names but I think the white dress cut is better on a smaller frame younger girl as the style is playful and key hole detail suits less cleavage - the studded embellishment gives it an edge that stops the overall look being too cutesy.