I converted my PS1000s to 4 pin XLR. Mainly because I planned on using the Mjolnir amp, which ONLY supports balanced connections. I have since ended up with the Bryston, which has both Balanced and SE outputs. I have a fully balanced NFB1.32 DAC, the Bryston BHA-1 and my PS1000s connected into the stereo balanced output. It sounds absolutely amazing to my amateur ears.
I didn't do a ton of A/B testing but I would say in the balanced configuration, it sounds cleaner, punchier, and with an even bigger soundstage. But that's a function of the amp design and characteristics. These headphones sound great in either configuration, so I would make the decision based on the hardware you plan on using.
If you know how to solder and can use a multimeter, then it's a breeze to re-terminate the stock cable to 4 pin XLR. It has 8 wires: 2 red (left +), 2 white (right +), 4 blue grounds. Using your multimeter set to "continuity", touch one end to the red or white wires and the other end to each blue wire. When you hear scratching and/or see the multimeter respond, you know you have the correct grounds. Then just twist each of the 4 pairs of cables together and solder to the XLR with
this pattern. If I can do it, anyone can.
Regarding SE outputs, it's easy enough to either convert back or just have a custom adapter cable made. I had one made for
$17 at Kvconnection which works perfectly. Rob is great and will make about any cable you need.
HTH