A few more questions to add to your decision making process:
1. Which dress fits your setting best
2. Which would look best with your FI's attire
3. Which one can you see yourself in all day/night
4. Which one represents your personality and how you want to feel on your wedding day
I too was in the same situation - I tried on about 5-6 dresses at 3 different shops and had it narrowed down to 4 VERY different ones (I had something specific in mind but wanted to keep my options open because sometimes you are really surprised). They all looked good on and all were in the same price range. I gradually started eliminating them for various reasons - one I decided was perfect if I was having a hometown wedding - I felt like I was walking the Oscar red carpet, but ultimately thought it wasn't right for our tropical laid back setting and would be annoying to maneuver in all night. Another one was totally beachy but not really my style so I knew I wouldn't feel confident. The third was fabulous - very Sex and the City, very bold. I loved it, but eliminated that one because it would have looked out of place in the Bahamas and we would have had to change my FI attire. I chose the one that was what I had in mind to begin with and thought to my self I should have known to just go with my gut. But I did really think it out and rationalize the decision. i am SO happy with it - and while I didn't know it was the "one" on the first try, when I went back to order it,i knew I had made the right decision. I feel like "me" but not ordinary me - special occasion vamped up me. It fits our setting, it fits my personality, and I can see myself comfortable and confident in it all night. I think FI & I will totally compliment each other and exude the fun, laid-back atmosphere we are trying to create.
As a side note, my bridal ship called yesterday to say the dress is here - soooooo excited!