Another vouch for wefwef. I’ve been trying it since yesterday and it’s really good and fast.
Regarding kbin, the main problem that I see is that it isn’t transparent about in which server a community (aka magazine), so there are lots of kbin self posts that actually are in other servers (like lemmy.world). Thats a problem when you’re trying to understand how this fediverse thing actually works.
The question could be changed to: “what’s your favorite programming language?”
I would said that this is a subjective question, as everyone has different opinions in expressiveness and design, and the productivity also depends in your experience.
On my case, this language would be Ruby, as that’s where I feel at home.