Hi mosh513,
Welcome to the Mattress Forum! 
This question is asked quite a bit, and you can read quite bit more about the difference between SBR and NR rubber in post #2 here.
All latex foam you encounter, (SBR, NR, SBR/NR, Dunlop, Talalay) will be a very high quality and durable material. The choice between Dunlop or Talalay for the core will be more one of personal preference and potential price differences. Dunlop, in the same ILD range as a corresponding piece of Talalay, will tend to have a bit more “dense” feel, which is why many people prefer it for the lower layers of a component mattress. You can read more about Dunlop (of either type) vs Talalay latex in post #7 here.
Phoenix