Mainly DX.

Deno has many of those things now, but my past experience wasn’t good. The first versions of Deno had a lot of friction; Bun however was more or less useful from day 1.

There are still some points of friction, but I'm content with it otherwise. The problems Deno resolves for me far outweigh the problems it introduces these days. I think the inflection point was roughly a year ago for me. Prior to that I really wanted to love it, but I ran into too many issues with the tooling I used most often. It was pretty frustrating. These days I rarely encounter anything at all, and I miss it a lot when I use other runtimes.