Hi Jade,
Price differences between different mattresses made by the same manufacturer generally reflect the differences in the cost of manufacturing and the different materials and components in each mattress although the margins in higher budget mattresses are often a little higher as well.
The Ultimate Dreams Eurotop is closest to the Brooklyn Bedding Bamboo Bliss (both have a 3" layer of latex that can be exchanged over a polyfoam support core) and you can see the differences between them in post #16 here.
There is also more about the advantages of the Alexis vs a mattress with thinner layers of latex in post #2 here. The Aloe Alexis has an additional 3" layer of latex vs the Bamboo Bliss which is a more costly material. This would provide more options to customize or fine tune the mattress (either before or after a purchase) either with choosing the initial layers or by rearranging or exchanging layers and with 6" of latex instead of 3" it would be closer to the “feel” of an all latex mattress. Since latex is a more durable material it would also have a durability advantage over the Bamboo Bliss as well for those who are heavy enough to sink into the deeper layers of the mattress because latex is a more durable material even than 2.17 lb polyfoam (which in turn is more durable than 1.5 lb polyfoam).
Phoenix