I have both. The double seem to take longer to bloom and they are not as fragrant as the single. That is according to my nose.
They are not hardy in my zone so I grow them in pots and bring the pots in for the winter. My single bloom first and the doubles bloom much later. It is not bad because I have flowers later with the double but because the fragrance is not as strong as my single I place the pots on the table close to sitting areas.
