I've used used Parcel for a few projects this year and really enjoyed it for the most part. I've found it's basically effortless for building static projects, but its lack of documentation can be frustrating when errors pop up (e.g. I was stuck on an older version for a while due to some issue with a newer release) and I still haven't quite figured out the best pattern for extracting the hashed bundle names for use in other places.

That being said, Webpack 4 (released months ago) shipped with a similar zero config option, so I'll likely go back to it for future projects.