I recently switched from conventional Dynamic speakers to Planar magnetic ones, and what revelation in terms of transparency, expansion of sound stage, sweet treble and real bass.
I will not pay £5K for any headphones and I am a big fan of Yamaha products, though these bad boys are way above my league.
Poor people and ordinary mortals like most people I know, need not spend guzzillions on a good pair of planar magnet headphones, there are quite a few manufacturers out there, selling PM headphones at sub £500 price range, Monoprice Monoliths 1060, 1060C, 1570 and 1070 are all good designs and the Chinese manufacturers such as Hifiman and Moon-drop, Gold Planar are excellent choice.
I have recently purchased the Hifiman Edition XS (open back) stealth planar magnet for £407 (reduced from £499), truly tear evoking, 'I just want to hug somebody now and tell the world I found my true love speakers'. Really sold on the technology, so in addition to the XS's, I also got myself a portable Gold Planar (closed) headphones for my DSD512 DAP player. These costs a mere £85 including delivery. It's going to be a long wait for those, courtesy of AliExpress.
These little planars are inexpensive but it does give you a flavour and if you want something bigger later on like the top end Audeze LCD-XC, it's worth starting small before you splash out.
The Hifiman Edition XS's like many full size planar magnets need a good powered source, so fixing them on to your mobile, unless you use a portable DAC dongle, makes no sense, you won't hear it's potential. I'm using Topping E50 DAC with external linear power supply via Class A Lehmann's head amp, this is a magic combination in terms of dynamics and delivering sound that is faithful to the source.
My current headphones are on eBay, as much as I love my Yamaha HPH-MT5 and Audio-Technica ATH-M40x headphones, I need to recoup some of the costs!