We produce publications which are PDFs and would like to make them available in ePub format. What services or software have a solid reputation which you can recommend?
What format do you start with? In other words, what format do you use to generate the PDF?
For example, if you start with HTML (or Markdown, or any other format which is easily converted to HTML), then it is relatively easy. Simply generate the ePub from the source HTML file(s). After all, an ePub file is simply HTML under the hood with some extra meta-data and packaged up in a specific way. Pandoc is a great place to start for something like this.
Pandoc does include support for converting to/from other formats such as MS Word. However, if you have any fancy formatting, that is likely to be lost in such a conversion . To retain formatting, you will need to use a specialized tool which converts directly from the specific source to ePub. For example, Apple Pages provides a built-in feature to export a document as an ePub. Similar features/plugins may exist for whatever tools you are already using.
Calibre is good for this.