Hi Adidas,
Like any other layering combination … it’s a preference and a firmer layer on top over a softer layer in the middle would be attractive to those who liked a firmer sleeping surface with some additional softness and pressure relief underneath. You can see more comments about dominant layers in post #33 here.
Assuming you mean a soft layer at the bottom … then rarely if ever (outside of a finished two sided mattress where it is a side effect of the design … see post #3 here). Having a medium layer on the bottom with a firm in the middle and a soft on top would be one of the ways you can rearrange the layers so that the firm layer is closer to the top of the mattress to improve the firmness of the support layers. Medium on the bottom would be fine if that was the arrangement that was the best match in terms of PPP.
They are both members here which means I think highly of both of them and I believe they compete well with the best in the industry. How any of their mattresses compared would depend on the specifics of the mattresses you were comparing. If you were to choose one of the mattresses from either or both of them among your “finalists” they would both make good final choices and I personally wouldn’t hesitate to buy a suitable mattress from either of them.
Phoenix