I love both... I think Felicity Juliette or Juliette Felicity would be gorgeous! Have you thought about nicknAmes? Perhaps nn's could sway me one way or the other but I like both about equally!!!
I prefer Juliette. Depending on your last name Juliette Felicity would be pretty.
I enjoy Felicity considerably more. Juliette is nice (I do prefer Juliet in spelling, though) but Felicity feels so fresh and beautiful, while Juliette is slightly more common and well-known. But you really couldn't go wrong with either!
Just a few off the top of my head...
I actually really like the flow of Felicity Juliette. Juliette Felicity is cute too. Or go with Felicity Julie/Julia/Jules. Then you could use both of your favorite names - which, by the way, are beautiful!
Both names have their appeal, though my favorite of these two is definitely Juliette (& love that spelling!) ;D Best wishes!
I prefer Felicity! And I prefer Juliet over Juliette. But I think you should go with whichever sounds best with your last name and the middle name you want to use. They'd make nice sisters too.
Juliet is one of my fav names! Felicity is nice, but I loooove Juliet.