Hi:
Leaving aside that you referred only to my competitors product and not our original which coined the term REGEN.
Also leaving said that USB "noise" (other than on the VBUS) does not really exist and that the mechanism by which hub-chip-based "regenerators" improve SQ is by improving signal integrity (as see on a eye-pattern) and impedance match--thereby permitting the DAC's own USB input PHY to generate less ground plane and packet data noise inside the DAC (the sort of stuff that sails past even internal isolators and modulates the DAC master clock).
The answer to you question is yes and no. Sorry.
What I mean is:
While my personal Holo Spring Level 3 sounds great via USB--with a pre-production unit of our new ISO REGEN in front of it--it still sounds better driven by the IS2 output of the SU-1 (also with my ISO REGEN proto in front).
I attribute that to the world-class Crystek CCHD-575 audio master clocks in the SU-1, which--and this important here--fully become the master clocks for the Spring ONLY when the I2S connection is used. (For AES/SPDIF, these same clocks get embedded into the data and then the DAC uses PLLs to extract and reclock that--and I think its cheap clocks get back in the action with that connection.)
So while the Spring's USB>I2S input board is neither terrible nor special (just pretty standard XMOS), the SU-1 is a good piece with fantastic clocks--which are best utilized via the I2S connection.
Hope that makes sense.