Since no one commented, here’s mine:
The Slash 3 has more gain than simply plugging into the bottom of my iPhone and going to RCA’s.
The soundstage with the Slash 3 is huge, vocals and highs are much better.
The cables on the Slash 3 might be better than my iPhone USB c, but neither are exotic by any means.
Overall, it rocks! For the price, size and flexibility you get with the Slash 3 - I recommend trying it for your car, boat or second system.