I play unlocked on every hero with quick cast on. If I need camera lock I’ll just press space bar.
I will admit however that sometimes I die to something I didnt see coming because my view wasn’t centered on my hero and i wasn’t looking at the mini map, but this is extremely rare and embarrassing when it happens…
It depends on what I’m playing. If I’m running a tank or melee hero I usually play locked. I’ll play most other heroes a split of 50/50 unlocked. It also depends on how I’m feeling since unlocked is a bit more work for me.
unlocked always. It makes game much easier for both overall awareness and for hitting skillshots. You can just hit space to centralize camera on hero instantly if needed.
I play with both, but for tanking and heroes like Gall, I prefer Locked. Even with the Locked option, I am still moving my camera around fairly often, either by dragging it or using the mini-map. I just find it easier to have it automatically recenter when something happens to my hero, at least while tanking.
I always play unlocked. Was once forced to play locked due to a settings bug and I found it nauseating.
I hold space when I cant figure out where I am.
Unlocked always.
Unlocked.
If I’m playing mage or healer I like the screen more in the direction of where my spells are landing. However, I sometimes hold spacebar when changing lanes while mounted, in case it takes me on some weird pathing.
Unlocked always no matter which hero i’m playing. i feel more comfortable with Unlocked camera but with Locked makes me feel weird lol
Locked camera makes me dizzy and I prefer to have control over what I see rather than the position of my hero demanding it. I like to watch distant lanes on occasion and unlocking camera each time I do it sounds like a pain. I admit it does hurt my situational awareness a bit but I overall I just prefer the freedom.
Asides from what everyone has said already, locked camera will just screw you over. If you have a long ranged ability and you want to target/track something just off screen, you can’t because your camera is being tethered. (Good luck clicking minimap fast enough in the heat of battle when you could have simply scrolled)
I get lost with unlocked camera. It’s absolutely horrid. That and when you hero is near an edge of the screen, you can’t see anything on the other side of that edge. I like to see everything around my hero, rather than just one edge. I rarely play anyone who is long enough range that it matters
Unlocked, i use space bar when i need to follow myself closely, or get back to me instantly. Also the f keys foe checking on your team mates is a thing.
F keys for teammates? New thing I learned.
Genji locked, everyone else unlocked.
What bothers me is that locked only allows you to go ~1 screen away from your hero, it’s like having boundaries. Unlocked lets me scroll wherever I want. Yes, I can click the mini map, but sometimes I keep scrolling to follow the flight just to be locked out because the final 1/2 screen is not allowed anymore.
Plus it bothers me that the camera jumps back to my hero too quickly. I might travel from top to bottom and already have my camera fixated on the fight there to keep track of the abilities and all of the sudden the camera jumps back to my hero waltzing through the forest.
Locked camera has its perks, but too many disadvantages that cannot be turned off.
You should ALWAYS play unlocked, it allows you to see the battlefield much better. I doubt any good player plays with locked so its worth learning unlocked if you want to improve.
I play with my camera locked, but I am aware of the minimap. Did you know you can interact with it? 
Unlocked . Nothing’s worse than not seeing player positioning
Mostly locked camera. Occasionally turn it off for shot stability.
Makes it easier to micro since you do not waste mouse time repositioning the camera as much.
I can’t even imagine playing with locked camera.
It’d be like asking if I drive with my head strapped to the seat so I can’t check my sideview mirrors.
Unlocked, but I set my spacebar to focus on my hero + lock/unlock camera.