Hi amoureux_de_chocolat,
You can see some comments about the Ultimate Dreams Eurotop vs the Bamboo Bliss (and the Cotton Camilla) in post #16 here. From a materials perspective the Bamboo Bliss would certainly be “worth it” since it uses higher quality materials and components and has other benefits as well but from your own personal perspective it would depend on your weight (higher weights will benefit more from the increased durability of the base layer in the Bamboo Bliss) and how you felt about the other benefits that would go with the higher price of the Bamboo Bliss (wool in the cover, a washable cover, and a more liberal exchange policy) and which one was the “best value” to you based on the parts of your personal value equation that are most important to you.
I checked the topic that included the information about the Evosleep Bio-Temp Retreat and unfortunately the original poster never did find out the specifics of the layers that I would want to know (see here) so I would need to know the rest of the information about the mattress that is “missing” (see this article) before I could identify any weak links or make any meaningful comments about the materials in the mattress. If you can find out this information and post it here I’d be happy to make more comments about it.
Once you are down to finalists that are all choices between “good and good” (and you can only confirm this with the Evosleep once you have the missing information) then your final choice would depend on how you feel about a local purchase that you can test in person vs an online purchase that you can’t (but has options available to exchange the comfort layer if you need to based on your actual experience) and once again on how they compare based on all the other objective, subjective and intangible parts of your personal value equation that are important to you.
Phoenix