Hey Laaandry
Welcome to the Mattress Forum! :).
Thanks for the post. What did Brooklyn Bedding tell you the difference is? There as been some discussion of these new mattresses since Q4 2018.
Below are my cut and paste from their website. The signature has the 2" Titanflex, which is one of the newer memory/poly foams. You can read more about the newer generation of new generations of polyfoams here.
The signature has the 2" Titanflex and 2" Energex foam, and the Bowery hybrid just has the 2" comfort foam (whatever that is) and also foam in the quilt package. Signature also markets some temperature regulating qualities. Clearly, there is a fairly big difference between these two products. I have not slept on them side by side. Which one is better for you is an entirely different question. Have you tried these mattresses?
Signature:
Offered in three levels of firmness to let you decide the level of support you need
Features a 2" top layer of patented TitanFlex™ foam, combining all the contouring properties of memory foam with the responsiveness of latex
Designed with a 2" layer of firmer transitional Energex™ foam for deeper compression support
Engineered with a 6" base of up to 1,024 individually encased Ascension™ coils for increased support and decreased motion transfer
Infused with cooling TitaniumGel™ to moderate your body temperature throughout the sleep experience
Finished with a 1" high density foam base for added durability and reinforcement of individual coils
Bowery Hybrid
Offered in a universal, medium firmness that balances just the right amount of pressure point relief with optimal support
Features a 1" layer of quilted, gel memory foam that resists body impressions and provides optimal cooling comfort while you sleep.
Designed with a 2" layer of comfort foam to create a gentler transition to the mattress core.
Features open cell technology for increased airflow and breathability.
Engineered with a 6" base of up to 1,024 individually encased Ascension™ coils for increased support and decreased motion transfer.
Finished with a 1" high density foam base for added durability and reinforcement of individual coils.
Thanks let us know if you have other questions.