I've had a steam controller for a little over a month now. I bought it specifically for gaming while on a treadmill, as keeping my right hand still enough to use a mouse while walking is pretty much impossible, and it's performed that job admirably. I played essentially all of Mirror's Edge Catalyst with it, getting high ranks in the time trials and everything (and yes, playing first person games on a treadmill can be disorienting, I still catch myself trying to turn in real life a little when I want to turn in the game sometimes).
However, even now I'm still not completely sure how to just hold the thing. My default position and the one that feels more natural is to have my pointer fingers on the bumpers and middle fingers on the triggers, leaving my ring fingers and pinkies to actually grip the controller and control the grip buttons, but this position means I can never have a really solid grip on the controller. The grip buttons don't feel good to press and it's easy to press down a little on the triggers when I try, the bumpers require me to brace my hand a tiny bit against some part of the controller because the ring/pinky grip is pretty weak on its own, and to stop myself from accidentally pressing anything I have to hold the controller a little gingerly at all times.
The alternative, the more "standard" controller holding position, is to just have my pointer fingers on the triggers while all my other fingers grip the controller (save the thumbs, of course). This is more comfortable in general. The grip is much more solid, the grip buttons feel good to press, there's no bracing or gingerness necessary, but there's one massive problem: the bumpers are way too high and way too stiff to use effectively with this position. It's a complete dealbreaker. If this wasn't the case there would be the tiny disadvantage of slightly slower access to the bumpers compared to the other position, but I'd be totally willing to sacrifice that for greater comfort.
I wonder what position the controller was intended for. If it's the one I use, then the basic shape of the controller needs to be revised to allow for better grip. If it's the "standard" one, the bumper and trigger positions need to be completely rethought. Either way, the stiffness of the bumpers is unfortunate, but that's a common complaint from what I've seen. How are you guys holding your steam controllers?
Edit: Whoops, I see this was actually just being discussed. I hold the controller the same way as Durante and UnaiGamer. Do you guys have a solid grip with that position? It never feels perfect for me. The bumpers are really just no good regardless.