My brother is using the Roccat Kone. I'd say it is quite comfortable, and he has it for a while already (I think).
I would prefer a Logitech G600 myself, and think it lies very comfortably in my hand. A good size aswell, my hands are fairly big so it's hard to find a mouse that's comfortable in my hand. With the Naga for example, I easily got cramps in my hand.
Friend of mine uses the "Cyborg" mice. And he sold his soul to that brand. But I think they're more about looking cool and high-tech then being comfortable and useful.
Not sure what else for advice I can give. Hope you will manage to figure it all out!