Hi Rmilbank,
You are certainly looking at some good options.
Both of these are great value and would be among the better options that are mentioned in the children’s threads I linked but they have different designs that are more of an apples to oranges comparison. You would be comparing “good vs good” and I don’t think you could go wrong with either of them in terms of quality, durability, or value so any final choice between them would depend on the parts of your personal value equation that were most important to you and which one you were most attracted to for personal reasons. I also agree that the upgrade to the Pure Echo two sided version would be well worth the extra cost.
I would need to know the specifics of what was inside this mattress to make any meaningful comments about it (see here) because the name of the manufacturer or the “regular” selling price aren’t nearly as important as how it compares to your other finalists.
Again … I would need to know the specifics of what was inside the mattress to make any meaningful comments about it. A “chemical free” fire barrier (which all of your other options would have as well) doesn’t mean the materials inside it are good quality or that it would be good “value” … especially if it’s made with lower density polyfoam.
Outside of any local options that may be available to you … some of the lower budget latex or latex hybrid options (including SleepEz and Mygreenmattress) I know of are in post #3 and #4 here.
Phoenix