Our own @Hazi59 did a thorough comparison with RNHP here:
I have one of these amps, too. One day soon I hope to get a full review up (it’s Jan 2021 as I write this). For those wondering, it has a studio-neutral sound signature while still retaining a hint of fun and smoothness, decently wide soundstage, and very good detail retrieval. I haven’t found many magical headphone synergies yet like you hear with RNHP; G111 seems to be more of a generalist by performing very well with a huge range of headphones. It also has power to burn. It’s spec’d at 900mW output into 300 ohms and 600 mW into 600 ohm. My listenening experience with it tells me you can believe those numbers. It will likely drive everything not named HE-6 or Susvara (which, spend more than $549 on an amp for Susvara anyway, please) easily. Consider these words a trailer…