I've tried evey dongle I could get my hands on and the S1 is still at the tops. Earmen sparrow is top notch too, it's got more power and a more foward sound. Btr5 is still very good to me also.
What I like about the S1 is it has a more natural tonality like the paw 6000, and it's fairly neutral. But the best thing is the staging, to me is really nice. I don't consider sonething like btr5 neutral, it sounds boosted and a bit v shaped- but still really good.
I use neutron and the Headphone setting and I can listen for hours. I prefer that sound to many + 1000 dollar daps I've owned. Of course they win on power output but I have relatively easy to drive stuff.
Sparrow can drive more stuff and has a more foward slightly aggressive/sharper sound. But S1 to my ears gets the tonality just right and it's very refined sounding.
My 2 cents. I didn't like quite of few of the other popular dongles, they sounded to me too compressed or digital.