Hi dreamthedayaway,
This is one of those questions where your choice would be based on personal preferences not “better / worse” and only each person can decide for themselves. The “weak link” of a mattress is generally in the upper layers of the mattress not in the deeper support layers (assuming both are good quality) so the durability or the support cores would not be a major part of my decision if all of the other durability factors are equal (such as the type and thickness of materials in the comfort layers and the other factors that are part of how durable a mattress will be for any particular person that are discussed in post #2 here).
Some of the things I would take into consideration though include …
A local choice that you have tested in person is always less risky than an online purchase especially if it is not returnable and in an apples to apples comparison where the local mattress is equivalent in design and value to the online mattress I would tend towards the local.
You may have options with a local purchase such as making an adjustment to the mattress after you have purchased it that you wouldn’t have with an online purchase that isn’t returnable.
I know a lot of people who are very knowledgeable in the industry who could sleep on any mattress design that they choose. If you interviewed these people you would find that some of them preferred all latex, some of them preferred a latex/innerspring hybrid, some of them preferred a memory foam mattress, some preferred an innerspring with layers of natural fibers, and there may be other preferences as well but I don’t think you would find any of them (or at least very few) who chose a latex/polyfoam hybrid as their “ideal” mattress. In other words this would be a budget choice but probably not a performance choice for the large majority of people.
An innerspring support core in most cases would likely be a little more costly than a polyfoam support core so this would probably be reflected in the price of the mattress.
The two main functions of a mattress are pressure relief and support/alignment and I personally place a high value on personally testing for both which is why I place a value premium (usually about 20% or so depending on someone’s “risk tolerance”) in an apples to apples comparison (and this isn’t quite apples to apples because of the different support cores) between a local purchase and an online purchase to decide on “equivalent” value.
Having said all that … both of these are among the best quality/value manufacturers in the country and each may have their own unique pros and cons that are either more important or less important to you. This is all part of what I call each persons "value equation (see post #46 here) which are all the objective, subjective, and intangible things that are an important part of a mattress purchase for each person and may be different for each one.
So I would compare the two on an apples to apples basis as closely as you can (taking into account the similarities or differences in materials in each mattress and all the other factors that are part of 'value") and then decide on which one has the better value based on the things that are most important to you including the importance of testing a mattress before you buy it. You are choosing between “good and good” and in terms of quality and value (as opposed to pressure relief and support/alignment terms and the suitability of a mattress for your needs and preferences) it would be difficult to make a mistake.
Phoenix