I substituted light sour cream for the creme fraiche based on what i had in the fridge, and omitted the vegetable oil to slash calories. Using a mixture of purple, yellow and red potatoes adds pretty color to the salad. I think the sour cream and the lemon juice together made the dish a bit tart (and yes, I recognize I'm criticizing my own substitution), however I liked the fresher, cleaner taste more so than the typical mayo-based potato salad. Served to guests and while everyone ate it, no one commented on it. Would be good hot or cold. I would make again, but this won't go down as an all-time favorite.