Listened to the Walnut a good 4 hours straight today, really happy with it, I also took it to the gym paired with Koss Portapro, usually I take Hum Pervasion as my gym dap, but the Walnut did not disappoint, the Hum was not missed at all, actually I enjoyed the Walnut more than the Hum in the context of the gym.
Some daps I can't use at the gym at all, like DX90, Pono, QA360LE, P90SD, N6, X7, etc, basically every dap I've had other than ZX1/2, Hum, Zishan, and Walnut, this is because all latter daps have a type of dynamic and 3 dimensional sound which I can't go without at the gym, while most other daps daps kinda sound a bit flat (in sound stage, dynamism, contrast) and thus boring, even if they are technically proficient and transparent.
I'll be buying one or two more Walnut's just to mod them with different capacitors for different sound sigs, I love this little Walnut, it's not a giant killer in sound quality, but it just sounds enjoyable to me and I can listen to it all day, it's a giant killer in terms of value for money in enjoyment and fun factor for me. Also I tried about 20 different opamps in the Walnut and all sound awesome, just different, some have higher noise floors than others, but you can't hear that with music playing and they all sound great, even though I have my favorite opamps with low noise floors, I could actually live with any one of the 20 opamps I tried, same goes for the Zishan. Two awesome daps.