After nearly a year in development, we're finally happy to announce the release of Ultimate Search 1.0. The plugin has been fully rewritten from the ground up to support faceting by unlimited combinations of custom taxonomies and post meta fields (like data created with Advanced Custom Fields).
We're offering a basic version of the plugin on the WordPress repository that can filter by categories and tags. In order to help support our development efforts, we're offering a premium upgrade for $25 (unlimited license, lifetime updates) which will allow you to select additional taxonomies and meta fields.
I'm sure there are going to be some bugs over the next few days as we learn how this plugin handles in different situations, but we'll be devoting our full attention to supporting it, and will be pushing out a bugfix release soon.