I'm not really sure, I haven't followed the development that closely... I know I tried it... and it was pretty close... when I was ready to switch, had done some testing, and had to adjust several of the defaults to be closer to the existing linter config. That said, the reformat/lint-fix was so fast, it wasn't that big a deal. Did it in two commits, one with just the linter config, another with the reformats in a separate commit.
The whole project can be scanned and reformatted and lint-fixes applied in under a second... the eslint config with TS took several seconds... as a precommit hook it felt pretty painful in practice, now you don't even notice it.
If they do as well for build options (once added), I'll be very happy indeed.
Vite is definitely an improvement over what came before (Parcel can be nice too). And yeah, migrating an existing codebase can be difficult, especially when you have other integrations (storybook, etc) that need to line up as well.
Just updating libraries in use can be really painful if too much time goes by.
The whole project can be scanned and reformatted and lint-fixes applied in under a second... the eslint config with TS took several seconds... as a precommit hook it felt pretty painful in practice, now you don't even notice it.
If they do as well for build options (once added), I'll be very happy indeed.