Hi Savanabanana,
A mattress that is the “best value” for you is always the most important part of any mattress purchase and it’s great to see that you did some great research and ended up making such a great choice. 
These types of choices between “good and good” can involve objective, subjective, and even intangible criteria that can be difficult to assess and it can be difficult to place an objective “value” on the differences between two mattresses when you don’t know for certain how they will affect how you sleep on each mattress (which is the most important part of the “value” of a mattress purchase). In some cases and for some people these types of “final choices” may even be a matter of “gut feel”. When you look back on a successful mattress purchase in many years from now when you decide to replace it you will remember much more about how well you slept and how long you slept well than you will about relatively small differences in price or features that seemed to be more important when you were making the purchase.
I think you did very well and I’m looking forward to your feedback after you receive it!
Phoenix