Hi Sleepless-in-Cali,
If the comfort layer and the cover was exactly the same in both mattresses it would depend on the specifics of the pocket coil and how it compared to the Talalay support core. If they are both sold at the same store then they should be able to tell you which one most people would find softer (although this would also be somewhat subjective and different people may have different opinions about which one was softer) but if they are sold at different stores the only way to know would be based on your own personal testing or experience because innersprings and latex have a different āresponse curveā and āfeelā (see post #28 here).
Phoenix