Never used milkman so can't say if it's better, but +1 for Bruno.
1. Very similar UX to postman (just minus the bullshit), so a very easy transition.
2. It's FOSS*
3. Most importantly of all, it has a cute dog logo.
* oof, just saw this on another comment: https://royathan.com/blog/the-api-client-hunt/
Bruno is VC funded.
The Hurl file format seems good, any new FOSS replacements should probably build on top