Lo there
I have a pretty average sized head and have tried both. They both fit pretty snuggly for me. The Dye system is well vented and very durable but I did find it a bit uncomfortable when I wore my glasses and the lense seemed to warp my peripheral vision (the vision swimming effect I think it's called)
I bought the proteus in the end as it felt better with my glasses. It must be said though. After I played with it once I did find a few problems with it. The plastic behind the ear piece had not been moulded properply so dug into the back of my head. This was sorted with a thicker beanie. Also the inner foam around the lense was put on scew. It might have been a one off but with the ammount of cash you spend on the proteus, you'd expect it to be put together decently. I'm a bit of a perfectionist.
Unltimately it's like Micah said. It's all up to you and which suits you better. Everyone's different. Good luck
Laters
Gareth