I don’t really use EQ because I like being able to have a consistent experience between different sources. I occasionally use my stuff out of my phone and since I can’t use EQ on that, I don’t want to get too used to a particular sound so I usually do mechanical mods instead.
The problem with higher end headphones is that they all seem to have a dip past 1kHz, so for a similar experience, I’ll need to shelf everything around 1-4kHz which would be possible, but that still doesn’t compensate for other headphones’ issues in that area. Right now I have a Utopia and HE6 on loan and even with EQ, it really isn’t right. HE6 has a plasticky timbre in the upper midrange and Utopia has a strange resonance around 4kHz that is consistently bothering me. The HD800 also has a bit of plasticky timbre even when I EQ it too, so as much as I wish I could EQ it, I’m never fully satisfied with it.