I have the Malindi, several pairs beach/caymen as well as many pairs of Croc flip flops.
I love Crocs, and nothing is as comfortable as they are, and I honestly can't imagine wearing anything else but Crocs to a theme park. I agree the Beach style is ugly, but they feel so much better than anything else, I just don't worry about how they look. And I think the flip- flops look fine.
I got the Malindi to wear to work -I am on my feet the whole time- and I don't have to dress up for work, but regular crocs aren't really appropriate. So the Malindi is perfect. They are way more comfy to me than any non-croc shoe (even athletic shoes or Clarks). But, honestly, I don't think they would work for me all day in a Theme Park. I don't know how to explain it, but they just fit my feet in a different way, like they could come off if I walked too fast or something. And they don't seem to breathe as well as the more open Crocs. They are perfect if I am going somewhere where I need to be moderately dressy/presentable but not rushing about or walking miles. For real park touring I wear my Croc Flip flops or Caymens.
I love Crocs, but I do find that several of the more "regular looking" styles are much harder to fit. At least for me.