Hi buckeye,
The layers and specs are on their sites but for reference the Spindle Abscond uses three 3" layers of either natural or synthetic Dunlop latex (made using a continuous pour process) and has a thin 3/4 inch layer of quilted polyfoam in an organic cotton cover. The layers can be rearranged or exchanged after a purchase (Note: Spindle is now only using 100% natural continuous pour Dunlop and wool quilting in their mattresses).
The Brooklyn Bedding Essence uses a 6" core of 100% natural Dunlop and a 3" comfort layer that uses the more costly 100% natural Talalay latex and has a cover that uses wool quilting in an organic cotton cover. Wool is also more costly than polyfoam and is a very good temperature regulator and is also used as the fire retardant in this mattress. The comfort layer can be exchanged after a purchase.
Dunlop and Talalay both come in a wide range of firmness levels so one isn’t necessarily firmer than the other although Dunlop has a higher compression modulus (gets firmer faster with deeper comprression) so if they both had the same ILD (softness level) and the ILD was measured with the same method then if a layer is compressed less than 25% then Dunlop would generally be softer and if a layer is compressed more than 25% then Talalay would generally be softer. They would be the same at exactly 25% compression.
Both of these mattresses use high quality materials and have no weak links in the mattress and both manufacturers are members of the site which means that I believe they compete well with the best in the industry. You can read more about the different types of latex in each of them in post #6 here.
Phoenix