Hi Jill71rdh,
I just literally went through the entire mattress purchasing process as you are right now-- from a bad first purchase all the way to family members calling me crazy for my obsession with understanding mattresses 
It can be seriously overwhelming.
I was looking at many of the Latex options as well, and I wanted to share with you why I decided on purchasing the Ultimate Hybrid from Arizona Premium. While all of these companies are considered great companies, I spent a thirty minute phone conversation and then over 15 emails with Ken at Arizona Premium Mattress customizing exactly what I wanted in my mattress, which is what solidified it for me. None of the other companies I called gave me the same amount of time or the customization options that he offered, and I felt really secure in my purchase at the end of it all.
Furthermore, the Ultimate Hybrid really seemed like the best value for the money, especially since I was able to add an additional 3" layer to the mattress and it was still $300 less expensive than the Luma Latex Slumber System. While Luma does have a free comfort exchange and free shipping, it seems like the “free” is actually built into their prices and they charge everyone a flat rate. At Arizona Premium you are charged the exact UPS price of your location–so depending on where you live it could be significantly less expensive. For example, I live in Virginia and my shipping was $175 because I live across the country. The exchange policy does charge you the shipping, but I also don’t think the UPS price of shipping one layer of latex is not going to be more than $50 (but I could be wrong?). That still is less than the $300 difference between the two beds.
The Ultimate Hybrid was about the same price as the Flexus QUADRA-FLEX; However, the significant difference to me was that the Ultimate Hybrid’s coils are well known Leggett & Platt that have been reviewed repeatedly as strong coils on Mattress Underground, whereas I could not find any information about the Flexus coils. In another forum post Phoenix suggests that they might be proprietary: https://forum.mattressunderground.com/t/l-p-coil-in-the-ultimate-hybrid-vs-quadra-flex-coil-in-flexus-comfort. Either way, there does not seem to be much information on their durability. Flexus also appears to have the same policy on returns and comfort exchanges as Arizona Premium, and the only difference is the initial free shipping. I think the knowledge of the components on the Ultimate Hybrid make that value stronger.
All that being said, there will be a longer wait to receive the Ultimate Hybrid from Arizona Premium Mattress compared to the other two companies, and it looks like at lease the Luma comes pre-made as opposed to assembling the pieces of the Ultimate Hybrid yourself.
That’s my two cents, and the reasoning behind my mattress choice just in case it helps you out at all. You can see in my own thread I tried 100 mattresses before I settled. I am excited to try my mattress when it comes. I hope this helps 