Personally, 6 is my favorite, and 2 and 7 are my least favorite.
I did some editing to 6 just to show how I would change it (hope' your okay with that)
1. First I increased the saturation
2. Then I increased the sharpness
3. Then I increased the exposure
4. Then I changed the temperature so the photo had a "warmer" feel
5. Lastly, I cropped some of the coast out, so it didn't seem so busy
IMO, 2 seems to dark, and the boat is just to "in your face", and IMO, you need to crop in on the people in 7 more, even more then you already have. And I would also increase the exposure a little bit more, and maybe increase the saturation.
Don