I never had the steam controller, Once I got very close to buying one but then didn't I have always heard mix reviews for it some love it some hate it, there's that learning curve to it so I am guessing those who don't are the one's didn't\couldnt as for other controllers I have had lots of experience with Xbox360's, DS3, DS4, and XB1's 1st gen and the one with a 3.5mm jack(it was the one I sold on PG with PC receiver)
Controller preference and what you pull most out of it depends on Games you play and the platform you are on
For instance, steam controller for sure is not Mouse replacements but there are occasions where is outshines XB1's and DS4
I have used DS4 intensively on PC using different clients even DS3 and I'd say if you have a laptop or a great PCI-E-E Bluetooth adapter (not dongle) and don't want to deal with AA batteries DS4 is best
Whenever I switch from XB1's to DS4 playing games like Forza etc not many people may have noticed it but Impulse Triggers on XB1's controller are amazing and DS4 suddenly feels like a step back but this one has its own list of cons, Xbox360 Controllers were supreme still many praise them on XB1'S, DS3, for instance, the Dpad and bumper keys on XB1's sure are clicky and feel responsive but with time they stop functioning and this is coming from a guy still having his 2010 360 controller in pristine condition
PS any PC users here were able to get a good Bluetooth adapter? I have always been on Gaming laptops or desktop Alienware and they often have amazing Bluetooth my new build thoughts unbranded mobo didn't came with Wife/Bluetooth built-in, hate dongles had a worse experience with em