Hi klphoto,
You can see a picture of some Mountaintop continuous pour Dunlop latex (which is what the Ikea mattresses use) with the 7 different zones in post #73 here (the smaller pincores are firmer and the larger pincores are the softer sections). There is also more about zoning in post #11 here and the posts it links to.
“Comfort” is subjective and different people will have different preferences for different types of materials or different types and blends of latex but there would be no durability concerns no (that’s what I meant when I mentioned there are no “weak links” in the mattress). There is more about the different types and blends of latex in post #6 here.
Phoenix