Hi valli,
You are certainly looking at some very good choices (Brooklyn Bedding who are members here and Don at Select Sleep Center who I also think highly of).
The best suggestion I can make would be to use the information and follow the steps and guidelines in post #1 here and when you have eliminated the worst choices and are down to choices between “good and good” then to use the parts of your own personal value equation that are most important to you about a mattress purchase to make your final decision.
It’s great to see you looking at good options though and I would always start with local testing so you can become familiar with different materials and mattress designs regardless of where you end up making a purchase.
Don’t forget that PPP (Pressure relief, Posture and alignment, and your Personal preferences) along with the quality and durability of the materials and your ability to make meaningful quality and value comparisons between mattresses by knowing what is in a mattress you are considering are the most important parts of any mattress purchase (see post #5 here)
Phoenix