Congratulations on your purchase, the N10 is an excellent product.
Regarding your question I would say it all depends on your DAC but for PCM AES/EBU is most likely to be the best.
For DSD most DACs won't accept DSD over AES/EBU so either use DOP or USB for Native DSD.
I am using a Hi Diamond Reference AES/EBU and USB both have given good results without breaking the bank.