The sweetest treble and minor usability issues
P1 is the best IEM I now have - and my other ones UE 900, NuForce EDC3 and a TFZ ain't bad either. P1 has the best treble of the bunch: full of detail and air, so sweet, never harsh, just like my big HifiMans. Planar magic! I use P1 with Radsone EarStudio which gives me LDAC connectivity, enough power (I never go above -12 dB) and app EQ option for some extra sub-bass. To me P1 is a bit bass-light. People seem to argue quite a bit on bass level on specific IEMs but this depends so much on tips and seal. With +3 dB around 40 - 80 Hz the P1 is perfect for me. I also got a nice short cable from HiBy.
P1 isolates less noise than my other IEMs. This makes P1 nice for office use since it's actually good to hear a bit what's going on around you. But I'd never use P1 on a bus, train or plane. Also, P1 is heavy for its size so I don't like to use P1 for gym, outdoor, or anything where I might jump around. Even with memory foam tips they don't stay on.
Summary: I love the P1 sound but I prefer other stuff when on the go.
Would recommend to a friend.