I've had several IEMs with balanced cabling for a while - HIFIMAN RE262, RE272 and RE600. I didn't have an amp or player with balanced output, so I just used the included TRRS-to-TRS adapters. Then along came the HIFIMAN HM-901. I go it with all of the different amp cards, but so far, I having so much fun with the balanced card that I haven't spent much time with the others. The balanced amp card is powerful and it sounds great on the above IEMs. I had recently gotten the Audeze LCD-X and LCD 2.2 and one comes with a balanced cable and it's an inexpensive option on the other. The HM-901 drives them easily. Same story for the HIFIMAN HE500 and HE400 and Mr. Speakers Alpha Dog. For the Alpha Dog and Audeze phones, I need an adapter to go from 4-pin XLR to HIFIMAN TRRS and that led me to Moon audio. They have HIFIMAN TRRS as an available termination on all of their cables, so I went a little crazy. I ordered the XLR-TRRS adapter and a Silver Dragon MMCX to TRSS cable to use with my Shure SE846 & SE535LTD, Westone UM50, UE900. Then of course, I had to get a Silver Dragon cable for Westone/Earsonics to TRRS. And then, Fitear to TRRS. Then balanced cables for the Sennheiser HD800 amd HD600/650.You get the idea. The cables are great and they all sound wonderful with the HM-901.
I am a big fan of the Westone W4 and when the W4R was on sale for $300, I picked up 2, one for regular use and one for use with a balanced TRRS cable. One small problem with all of this - the HM-901 is not very portable, so when the HM-700 player was released, I ordered one. It comes with the balanced version of the RE400 and while it only has 32GB of storage, it at least gives me a way to use all the balanced IEMs and still be very portable. I was just now listening to a balanced W4R with the HM-700 and it is is a very good pairing. The instrument placement is very solid and precise, and the whole presentation is rich and clean, with excellent timbre.
Eventually, I will have to do some direct balanced vs. single-ended comparisons (same IEM and player), but so far, I'm very pleased with performance of the HIFIMAN players with a wide variety of balanced IEMs.