Hi domiho,
The Sleep Options 8" memory foam mattress uses 2" of 3 lb memory foam which is a lower density and less durable material than I would suggest unless you you are only open to memory foam comfort layers and you are limited to a very low budget range and there are no other better options available (you can see the foam quality/density guidelines I would suggest here).
The Healthy Choice latex mattresses use 100% natural Talalay latex which is a much higher quality material (although it’s not organic) and there are no weak links in any of their mattresses although I would make some careful value comparisons since they are in a higher budget range than other mattresses that use the same materials. There is more about Healthy Choice in post #21 here and the posts it links to and a forum search on hcmattress or a site search on the exact phrase Healthy Choice (you can just click the links) will bring up more information and feedback about them as well.
There is more about the pros and cons of memory foam in this article and the pros and cons of latex in this article and there is also more information about the different types and blends of latex in post #6 here.
Phoenix