I bought this card out of curiosity and impulse, the idea being that if it didn't live up to expectations then I would on sell it.  My music is 99% digital and more recently Tidal HIFI streaming. Where possible I upsample music to DSD512 for what I find is optimum transparency, balance, and 3D sound stage. It's hard to explain but DSD just sounds better than the PCM original. I find native DSD recordings (DSD256) sound really natural - see NativeDSD for a rich range of recordings. 
 
The NU Audio card is being auditioned in my office system. This currently comprises a Windows 10 PC, i5 2500k CPU overclocked to 4.2GHz (about to be upgraded to a Z390 with i5 9600k), ASUS DS7.1 audio card, HiFiMan HE 4xxx headphones, Cambridge Audio 640r amplifier, and KEF ls50 speakers. My primary audio system is based on a dedicated i7 7700 PC, Daphile audio, Topping D50 DAC, Topping A30 headphone amp, and HIFIMan HD4xx headphones.
 
I have added the NuAudio card to a PCIe slot on my office PC. I have configured Foobar 2000 to upsample music to DSD256 for output to the card. Playback is either through the headphones and or LS50s. 
 
I am really enjoying this card , so much so, I am now listing my audio PC, DAC and headphone amp. Native DSD256 sound is really smooth, easily surpasses the ASUS PCM 192khz card, and is more natural but probably not as transparent as DSD512 through the Topping - main issue I suppose is the Sabre DAC vs AKM. Long term listening is effortless. The background is black (ASIO buffer set to max) and I hear no noise or interference irrespective of the PC processing loads which is a pleasant surprise. I replaced the op amps with a pair of Burson 5i-d which I recently bought on Massdrop. These were originally intended for the Topping A30. There was a noticeable improvement and highly recommended. I doubt I could tell the difference between the Topping and Nu Audio in a serious A/B audio test. Other reasons I am liking the card is the reduction in desk clutter, reduction in cables and ease of access. I can output 5.1 through the ASUS card, stereo through the Nu Audio. 
 
I also look forward to future software upgrades which I believe is probably the main advantage of this card. In particular the ability to play Tidal upsampled to DSD256 (would be nice if the EVGA provided their own player with DSD upsampling as part of the standard offering) and support for Foobar DSD processor (I am having to use Foobar ASIO Proxy). Also the means to support DSD512. The XMOS xCore-200 and AKM 4493 are more than capable of DSD512 - see the Topping DX3 Pro.  
 
Note I tried running the card using Daphile but could only get DoP128.

Been sometime now but basically the "velvet" sound of the akm 4493 vs the clinical sabre sound. Based on what I have read elsewhere and confirmed by what I remember the akm is less fatiguing and more musical; the sabre has a wider sound stage and brighter high end. Re the nuaudio I also  think a lot depends on the quality of your Mobo and power supply. I also liked the dsd512 support of the topping with the ability to upsample all music in foobar subject to the power of your cpu. The nuaudio still only supports dsd256.