[HiAudio]

Which one do you prefer? Which one is technically better for the sound?
 
My Senn HD 650 and RS 220 are oval shaped and I almost do not need to move it after it fits well.
AKG K712 is almost round. I do have the space to move then back or forth and perceive different sounds. Sometimes I like it all the way pushed back and some time to the forth and some times in the middle.

 

[CaveManta]

Lemme tell ya..after owning the Q701, I really have to vote for oval-shaped ear cups as being the most comfortable for me.
My Q701 has me, like you, changing how I wear it. But it's not just the ear cups; It's the auto-adjusting headband as well. It's okay though, because once I do feel good about how I have the Q701 positioned on my head, I finally stop fidgeting with it. I've just gotta get equal pressure on all sides of the ear cup.
However, wearing my M50, I don't feel the need to fidget my cans around for the right fit. They just sit over my ears as they should.
 
Wanna know what's worse than both of these ear cup designs? On-ear headphones!

They're torture!

 

[HiAudio]

I have to agree with you that adjusting the round ear cup now and then is a lot of hassle especially they move by themselves.

 

[CaveManta]

Every little move you make seems to change the fit. It's like you can't tilt your head, move your jaw, or do anything while you're wearing some cans.