@dciraldo I am an authorized Aurender dealer. The N20’s OXCO clock is a very high quality one and is worth using. You will get the best possible results sonically from you unit using it. Luckily your Berkeley also prefers an AES input, it should be a no-brainer to use this protocol over USB.
The N20 and N200 seem to have similar quality USB outputs, but it doesn’t mean the two units will sound the same. Everything factors into the sound of each unit, and with the much improved power supply and isolation the N20 offers, the sound quality of the N20 is considerably more full, tonally rich, and less-fatiguing over time in a considerable way… not that that the N200 is in any way a slouch - it is still impressive at its price range.
Aurender units can also play DSD natively or converted to PCM (using FPGA conversion to DoP format). This happens both in the N20 and N200.
The phased-lock-loop feature you inquire about is only for SPDIF outputs of the N10, N20 and N30SA as it is tied to the Aurender’s internal clock. This is unavailable with with N200 due to clock differences. Using USB completely disregards the internal clock regardless of model.
I have both the N200 and N30SA on hand for demos, and the performance of the reference N30SA is simply jaw-dropping. Feel free to reach out directly should you want to discuss Aurender units more deeply.