The P1 is more neutral with better extended highs. It is much harder to drive, and really requires an amp to reach its full potential, IMO. The B400 is more organic sounding and warm, but it also has better resolution and imaging. I found that it took a while to find a set of tips that gave me a good fit. They are very close in quality. Between the two, you can't really go wrong. The differences are fairly slight and neither has real detriments. I got my B400 with the Candy Cane balanced cable, which works well and came at a discount when buying with the B400. Otherwise, there are a huge number of cables available inexpensively on AiExpress. I recently picked up the Penon CS819 balanced cable and it is a stellar, beautiful cable for $55.