Today, it is expected that any dac over a $100 sound pretty decent with either improvements or a sound emphasis that perhaps provides a noticeable improvement or works better with one's amp, speakers, etc., that supports the increases in price.
A higher voltage output, better separation, a bit better tonality, more note weight, stage sizing on all axis, less distorted sounds, etc., etc., however minor differences to some are highly noticeable by others.
Functionality and capability also come into play. Build quality, Reliability.
Seems dacs these days have a lot to offer at nearly any price point.
But I remember the old TDA chips that Philips produced that could be so natural sounding, It was a budget chip that when properly implemented...it was nice. It may not have had the larger stage size or punch as some others, but it could give a more natural rendition.