The better feedback loop actually makes it worth it. Yes, we don't get soundness and performance when programming in TypeScript, but we do get better feedback in the editor along with great escape hatches for customizing types as needed. I don't know if I ever can go back to a sound statically typed language again, actually, TypeScript is just way too useful.
I feel exactly the same way. I thought I liked static typing more than dynamic typing until I tried TypeScript, but TypeScript feels like by far the best of both worlds.
I especially feel like null checking is impossible to live without, and I'm going to strongly prefer TypeScript over Go or Dart from munificent's list until they add null checking.
