Hi luxastraea,
The first place I would start your research is post #1 here which has the basic information steps and guidelines that can help you make the best possible choices.
The minimum guidelines I would suggest for memory foam mattresses are listed in post #10 here and there is a link to some of the better online memory foam choices in the first post I linked.
I wouldn’t consider any of the Ikea memory foam mattresses because they don’t meet the guidelines (the memory foam density is too low). You can read some of my thoughts about some of the other Ikea mattresses in post #3 here.
You can read some of my thoughts about Bedinabox in post #2 here. Again their memory foam density is lower than I would consider.
Brooklyn Bedding / Dreamfoam is one of the manufacturers that were invited to become a member here and they are among the best quality/value available. They also have the knowledge and experience to be able to provide you with useful information that can help you choose a mattress that is the best match for your personal value equation.
My role is to help the members here eliminate the worst choices that have obvious weak links in their mattresses and then to make more meaningful quality and value comparisons so that their final choices are between “good and good”. In your case one of the two manufacturers you are considering doesn’t meet the minimum guidelines I would use.
There may also be some good local options available to you and the better options and possibilities in the New York area I’m aware of are listed in post #2 here and there is also a more “categorized” list with some more detailed descriptions of many of them in post #7 here.
Phoenix