Hi pamadelic,
Just in case you haven’t read it yet … post #1 here has all the basic information, steps, and guidelines that you will need to make the best possible choices.
There is no “better or worse” only “better or worse for you” and It would depend entirely on which design was the best match for your needs and preferences in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences). Your own personal testing or more detailed conversations with the manufacturer if they are online is the best way to choose between them (see mattress firmness/comfort levels in post #2 here). Both designs could work well.
No … it would depend entirely on the specifics of the coil and the foam and how they both interacted with the comfort layers above them. Both good quality innersprings and good quality foam are not likely to be the weak link of a mattress. Every layer in a mattress interacts and affects every other layer so it’s the specifics of each material (there are many firmness levels of latex and many different types of innersprings) and how they work together with your body type and sleeping style and which “feel” you preferred that would make the difference.
Yes it will make a significant difference. The comfort layer (or the upper few inches of a mattress regardless of the thickness of any any specific layers) is the part of a mattress that you will “feel” the most when you first lie on a mattress.
You can read more about the different types of latex in post #6 herepost #2 here and more about blended and 100% natural Talalay in . 100% natural latex (Talalay or Dunlop) means that the core only uses natural rubber in its construction (no synthetic rubber) but a core is not made only of rubber because there are also various soaps, curing agents, foaming agents, gelling agents, antioxidants, and other compounds (sometimes including fillers) used to make the foamed latex core. The rubber content is usually in the range of about 90% - 95% or so of the final latex core and it’s the rubber content that is either natural, synthetic, or a blend of the two not the entire core.
Phoenix