I really dislike how fonts render in Sketch. There used to be a option to sub-pixel anti-alias fonts but they removed it for "performance reasons, and improved consistency with mobile platforms".
Out of curiosity, what platform do you design for? I often make designs for web and mobile web, and I want my text to look the same in my design tool as it does on the platform I'm designing for. Since mobile devices don't support sub-pixel antialiasing, I don't want it enabled in my design tool either.
I do design for websites and web applications. Mobile is a consideration of course but mostly desktop oriented.
I understand not everyone wants it but that was the beauty of having it as an option. Now it's just gone and those of us who do want it can't use it. Personally I never had a performance problem with it (plus it was off by default) so I was (and still am) very annoyed at it being removed.