Honestly, we just did the "free" sessions and bought a single day of PhotoPass for $20. Got over 150 photos at sunset and they are the best pics I've ever had of the family. Three photographers were set up and we visited all three, with slightly different views/backgrounds for each. The photographers spent more time with us than I would have expected and we got groupings of family, kids, parents, and individual kids. I'm sure the poses were similar with each group, but I don't care since it's not like I'm putting their pics on my Christmas card.
To be fair, though, we went a second time two days later and didn't get as many photos (around 100). There were longer lines so we didn't get as much time. And when we first arrived there was only one photographer since the others were doing private sessions. Once the private sessions were over, however, one of the photographers converted to "free" and we got in his line also.
Watching the private session, it looked like there were more creative poses. The teenage girl was further out in the ocean with her dress in the water and some more creative poses. So it all depends on what you're aiming for. For me, the $40 I spent on PhotoPass for 2 days was an incredible value! I have never seen my family looking so good in portraits, and I'll be using the ones of my son alone as part of his senior portraits. Our local studio was going to charge $80 in sitting fees with no photo rights. $40 for all the rights and photos in Hawaii... or $80 + $30/image to have photos in a local park. Hawaii PhotoPass wins hands down.