Hi sungirl,
I don’t know enough about you or the criteria that are most important to you and there are too many unknowns, variables, and preferences involved to be able to give you a meaningful answer. There is no such thing as “the best” in general so all I can do is to help with how to identify the criteria that are most important to you so you can choose which one is “best for you”. Arizona Premium and SleepEZ are both members of this site and like all the members here (and many other manufacturers and retailers that aren’t yet) I believe they both compete well with the best in the industry in terms of their quality, value, service, and transparency. Either one would make a great choice … especially compared to almost all of the choices that the large majority of consumers would otherwise end up making.
The first place I would always start (just in case you haven’t seen it yet) is the mattress shopping tutorial here which has all the basic information, steps, and guidelines that can help you make the best possible choice … for you.
If you are looking for “chemical free” or “safe” materials then I would also read post #2 here so that you are clear on the criteria for “safety” that are most important to you and on the differences between all the different terminology you will encounter such as organic, natural, chemical free, green, and safe and the differences and similarities between them so you can make informed choices about which materials fit your criteria and you are most comfortable with.
Once you are clear on the type of materials (or the type of latex) that you prefer then post #13 here has more about the most important parts of the “value” of a mattress purchase that can help you compare mattresses and companies and make a final choice based on all the objective, subjective, and intangible parts of your personal value equation that are most important to you and that you place “value” on.
This should give you all the information and guidelines that you will need so that this time you can make the choice that is “best for you” and if your final choices are down to Arizona Premium and SleepEZ then it would be difficult to make a mistake 
Phoenix