Wow! The cut and back of the second one is gorgeous!! But the first one is also very very nice! Perhaps survey your girls? It might be a good idea to have them try both styles though, sometimes it's hard to know what is more flattering until it's on! Or have your MOH wear one and bridesmaids wear the other!
They are both gorgeous and when I saw the first one I said that is the one I prefer...but looking at them both, I am starting to like the second one better.... How many bridesmaids do you have, you could always do both dresses!