One of the best maintained contrib modules. Main benefits: nicely presented forms with powerful conditional logic, YAML configuration, flexible user permissions, very clean data storage, secure. Codebase is also very much written "the Drupal way".
I'm currently using this patch to avoid AJAX errors - it's only necessary where you've both enabled Automatically save as draft when paging, previewing, and when there are validation errors, and are using a confirmation type like inline, that still uses AJAX to submit the form when there are no validation errors.
Troubleshooting install of webform external libraries: (Jan 2020)
Follow these instructions: https://www.drupal.org/node/3003140
If you get a composer SSL error, follow these instructions.
(specifically, you need to set
openssl.cafile in php.ini)