Which DAC is better ?

As you have a new system, use both DACs you have, identify what seems best to you. Get to know your system prior to the purchase of a external (3rd) DAC. Best to know what you are looking to gain with additional purchase.

@mesch i will definitely try both out first. Thanks. 

Try both, but I had an eye-opening experience with a Marantz outboard/stand alone DAC and headphone amp (with a Node 2i) and I strongly preferred the Marantz sound. Better highs and separation/spatial cues.

If the "voicing" is similar, there’s certainly a chance you like the onboard DAC in the Marantz better...