Which one of the stores do you prefer to buy and play your games on?

Steam, always; it's where my existing collection is and I've never had any issues using it (outside of some storefront loading issues during the big holiday sales). The one time I tried EGS, for I think it was the free copy of Civ VI fairly early on, everything was so bare bones and the launcher was really buggy. I soon gave up on it and haven't logged in since. If a game is EGS timed exclusive I just wait for the Steam release, and if it's a true exclusive then it may as well not exist imo.

Steam

Because whats the point of buying something on EGS if you are gonna get it for free eventually or get them for better deals/discount elsewhere (Humble, Fanatical, GMG, etc) for Steam keys.

Steam by a forgone mile. Even Tim Sweeney himself recently admitted the storefront is a buggy mess. Coming up on 7 years the storefront has been around and has no discernible progress that makes it stand out.

PC storefront have to be more than simply a place to buy games. EGS has that basic functionality at most, but that’s it.

Edit: I stand corrected lol

I'd be amazed if anyone here actually answers 'Epic' in good faith. That said, I love all the free shit Epic has provided over the years through the app (not just games).

GOG.

Steam 100% nothing in gaming comes close to steam atm

I just buy my games on Steam, but in the past i bought some games on Gog and Origin (EA Play). I got some free games from Epic too, but I just played 2 of them (DNF Duel and Cygni).

Steam, for sure. But GOG is right up there with them, especially with their latest move on mod integration. 

Epic tried to buy their way into the market with give-away tactics, instead of actually developing their services. And it shows. Heck; the EA App is almost a better pick.