I've just tried this in a 14SC; this size usually fits me well at the moment- it does so in the kimono maxi dress and the black tie-shoulder vest (I've just got a tad too big for the Really sizes in my wardrobe!)
But this dress fits a bit small on the bust: in my usual Candy Bliss type bra it's too tight and gapes, and pulls the waist up a bit; in a more minimising type bra it only just about fits, and still appears to be pulling the shoulder bit forwards. Also, the wrap is not 'fixed at the top' (I was considering putting a stitch in but it might be better in a bigger curvy size - for me I would have to try a 16SC) There is plenty of room in the hips though (so a 16 might be too big for me)
Other than that it's a nice dress - the colour is quite a dark 'cobalt' without being navy, and despite thinking I wouldn't like the frilly sleeve detail with my larger upper arms, it actually looks really good and doesn't draw attention to them.
I think because it's quite a dark blue, it would look good worn to a wedding - it's quite classy I think.
In summary - I would say definitely go up a 'curvy' size in this.