I eventually got round to having a listen to the Chord Mojo at our local hifi shop. It was using the salesman's phone as source and a pair of Sennheiser Momentum over ear headphones (my phone wouldn't work as it has a dodgy USB port). After listening to a few tracks (none of which were familiar to me lol) I found a noticeable difference on quieter tracks but no discernable difference on more poppy/rock tracks. Music with more space to breathe obv allowed the individual instruments to come out in the mix. My question is that would I find a similar performance with my own music library on my phone using similar headphones given that my music is 128kbps in my library? I have no idea what quality of file I was listening to in the shop.
I will be changing my phone soon so the USB port will become a none issue.