Hi FoamMattress,
Before considering any of these options I would read this article which can help you avoid most of the lower quality/value choices such as major brands or almost anything sold at the chain stores that most consumers end up buying.
Post #10 here has a step by step process that can greatly improve your odds of buying a much higher quality/value mattress than any of these that you are looking at and most importantly you will know the real quality and value of what you are buying.
A mattress is only as good as what is in it and with the major brands you are buying a mattress with mostly unknown material but which will include lower density/quality polyfoams (the weak link of the mattress) which will soften and degrade much more quickly than higher quality materials. In a few cases they may have higher quality materials but these are priced much higher than many mattresses that use the same or better quality materials made by smaller manufacturers. The loss of comfort and support that comes from the softening of lower quality foams (which is the main reason people need to replace their mattress) is not covered by any warranty.
The first step is to find the better outlets in your area that carry better quality and value mattresses and have the knowledge and experience to help you make your best choices. These are generally smaller independent manufacturers that are sold either factory direct or through better sleep shops across the country.
If you let me know your city or zip I’d be happy to let you know of any better choices I’m aware of in your area.
Phoenix