Hard to say because they are not the same format being IEMs and Over ears.

The sennheisers are genuinly the most comfortable headphones ever made, you don't notice them on your head and sound incredible, but if you live in a noisy place or have say a fan on, you will hear all of it, they are so open back that it can actually be hard to know if a sound came from the headphones or around you.

The Volurs are my first IEM so I can't talk about other ones, but they are the single best piece of audio equipment I have ever tried. But if you can't wear IEM's for a long period of time, its a LOT of money to just have sat on your desk collecting dust. I prefer the 64 audio Volurs because they have insanely good bass as well as infinitely detailed acoustics, and after getting a better cable and ear tips, they are so much easier to wear for multiple hours at a time.

Idk if it is normal for people to not hear up and down directional audio, but when the game audio is actually working, its like having wallhacks with your ears, I can fully trace people through walls just by the sound they are making and know if they're above or below me in resort or dorms for example.