Hi vincent,
The quality of the materials in both of them would be closely equivalent and the choice between Dunlop and Talalay would be a personal preference not a “better/worse” choice. There is more about how Dunlop compares to Talalay in post #7 here but the best way to know which one you tend to prefer would be based on your own personal testing or experience. Both use a high quality wool quilted cover that uses the wool to pass the fire regulations.
Both are component mattresses that are put together when you receive them and only require putting the layers inside the cover and zipping it up.
The number of layers wouldn’t make a difference in the quality of the mattress but the 3x3 layers would provide some additional options for rearranging or exchanging layers which may or may not be a factor in your choice (see post #2 here).
When you are down to finalists that are all choices between “good and good” and there are no clear winners between them then you are in the fortunate position that any of them would likely be a suitable choice and post #2 here can help you make a final choice based on your local testing, your conversations with each of them, your confidence about the suitability of each one, the prices, the options you have after a purchase, and on “informed best judgement” based on all the other objective, subjective, and intangible parts of your personal value equation that are most important to you.
Phoenix