For bundling JS web apps or libraries of more than moderate complexity, they all have serious issues:

- Webpack is just too complex; when you have issues with the build, you don't know where to even begin looking to fix things. In particular, tree-shaking seems to hard to get working in any reliable way. All the same, this is what we are still using in our project, but stuck at version 3.12 (the last version before 4)

- Rollup is sweet when it works. But, it demands ES modules. More seriously, recently I'm unable to get the Typescript plugins to work properly (or sometimes at all). It seems weird to me that such a basic bundling scenario is broken.

- Parcel can't handle advanced bundling requirements

- ESBuild was tried recently; despite it's promise and hype; it breaks down even for some relatively simple bundling setups; very disappointing

- SWC seems to not be progressing that well. Their docs are still sparse, and you don't hear of them much. So I'm not willing to invest time diving into it.

What bundler(s) are you using, and what's your experience with them?