Started with the Fidelio X2HRs, went to the X3s and while they fix the muddy bass that sometimes comes on the X2s, and I actually like the build/style of the X3s better, there was just something 'missing' with them. So I went back to the X2HRs, such a good value headset to buy at the moment given the price of them. There is something quite cool about the really industrial look of the X2HRs.
Had the DT900 Pro X's arrive today and first impressions are really good. Will probably sell the X3s at some point given I've barely touched them and keep the X2HRs along with the DT900 Pro X's. Really wish Philips hadn't changed the sound profile of the X3s as much because they're a lovely set of headphones, with the option to be balanced.
I do have to say I prefer the memory foam used in the Fidelio ear pads as well, and they are a bit bigger than the DT900s. Anyone with big ears might find the DT900s quite snug, whereas the Fidelio's definitely give more breathing space.
I tune my headphones to this
https://www.reddit.com/r/oratory1990/wiki/index/list_of_presets with Equilizer APO and Peace. This video while a little long and rambly does at one point show how to read the preset PDFs and put the values into Peace for your headset
https://youtu.be/uWQ-DtHe24E
All headphones run through a Fiio K3.