Hi commonko,
The first place I would start in case you haven’t read it yet is the tutorial post here which has alll the basic information, steps, and guidelines that can help you make the best choices … and avoid the worst ones.
You can read more about Bedinabox in post #2 here and I would avoid any memory foam mattress that used more than around an inch or so of memory foam that was under 4 lbs or didn’t meet the guidelines in post #10 here.
Mattress reviews are also among the least effective ways to choose a mattress (see post #13 here about reviews).
It sounds like it could be the same mattress but I would still want to confirm the density of the foam layers in the mattress. If you can confirm the specs of the Eco3/Island Dreams (thickness and density of all the polyfoam or memory foam layers) I’d be happy to make some comments about it if it’s any different than the mattress mentioned in the thread you linked but if it’s the same as the other thread then the foam densities are higher than the Bedinabox and would be within the guidelines.
Some of the better options I’m aware of in the Hawaii area are listed in post #269 here. There are also some threads that include some discussions and feedback with various forum members in Hawaii in this thread and this thread and this thread and this thread and this thread that may be helpful 
Phoenix