Hi Katigraci,
The first place I would start with your mattress research is post #1 here which has all the basic information, steps, and guidelines that can help you make the best choice.
One of the links there is to the mattress shopping guidelines here which suggests avoiding the major brands completely because of their poor value and because of their use of low quality materials in the comfort layers which are the weak link of most mattresses.
In most cases they don’t disclose the quality/density of their foam but Jordan’s is one of the few (and perhaps the only) exception to this across the country. The Portola Hills is particularly poor quality and isn’t really suitable for an adult mattress and at best I would consider it for a guest bedroom or a “throwaway mattress” for shorter term use and even then only if it was a much lower cost. While the foam quality/density in the Stockport Ultra uses slightly higher quality materials but they are still not suitable for a mattress in this price range or for a one sided mattress. I would only consider the use of 1.5 lb polyfoam (in layers more than an inch or so) in a lower budget mattress or in a mattress that was two sided to extend the life of the mattress. Even then it also has some very low quality 1.2 lb polyfoam in the mix and I would avoid a mattress with this much low quality foam even in a much lower priced mattress.
So the Stockport Ultra uses better quality materials than the Portola Hills but both are poor quality and value, especially for their budget range, and I wouldn’t remotely consider either of them.
Overall … you will be much better off if you avoid the major brands and focus on smaller independent manufacturers that are sold either factory direct or through better sleep shops across the country.
You are fortunate to be in the Boston area because you have more of the smaller manufacturers I would focus on than most areas of the country. The Boston list is in post #2 here and post #2 here has some links to posts and threads with feedback about some of them as well.
Phoenix