Actually, I find the 3.5 sounded better than 2.5 balanced but then again, I only spent 1 hour on balanced (I was trying out balanced cables for my IEM but when I used the 2.5mm, it sounded less full tonally than 3.5mm with less focused imaging and a bit more fatiguing/bleached tonally) while I'm over 500 hours with the 3.5mm listening. Pretty much cured my itch of switching to balanced since I find the 3.5mm sound better for my taste. I did realize that noticeable burn-in effect (on the 3.5mm) after half a year of listening and the sound settled in its best state after that.
Interesting will share my experience with 2.5mm soon. I so far find the Se to sound a little intimate and not as layered as a balanced would offer.
Though with burn in I felt the sound to open up and now the se sounds much better and higher in sound details. The slight thickness has cleared and feels a little more open and less intimate.
I like the thickness in sound that the se offers.
I am hoping that the balance stay as thicky but with more precision and very open soundstage and less intimate.
Still sp2000 sound is very attractive hard to stop.