I got my SE535 ltd red today. Coming from the wonderful Sennheiser Momentum IEMs, it's still quite a step up. I'm running mine through my smartphone, HTC One M8 (I'm a huge fan of Spotify, despite not getting the best possible quality the massive library is something I could never give up on) and a FiiO E18.
I'm only just starting to get into the audio thing, so it's all a bit new for me. I've been playing piano for over 15 years now, and studied music theory/history after work, so I do know what I'm listening to.
Wanting to step up my game a bit, the sound of these E535s is amazing once I found the right sleeves to get the best fit. The only thing that bothers me is the stock memory cable. Maybe I need to break it in, but it's not properly fitting around my ear and is just too stiff.