As stated, the accuracy and formatting will vary based on several factors.
The output quality is governed by the source material. PDFs fall into two categories: True PDFs and Scanned PDFs.
True PDFs are files that were created by an authoring application, like Microsoft Word, Google Docs, or Adobe Acrobat. These files are vector-based and contain encoding information that makes the conversion process more accurate affair.
Scanned PDFs are raster-based files similar to image files, like JPGs, or bitmap files. It would be as if you took a picture of a document with your phone or scanned a printout with a document scanner. Scanned PDFs that are converted to Word documents are rarely perfect and will likely require manual intervention to correct imperfections.
Scanned PDFs will have difficulty with non-text objects in a document, like tables and images. The layout and placement will have a high likelihood of requiring document touch-ups.
Fonts and numbering may be less than stellar, but the bulk text is likely to be spot-on. In many cases, that’s the most important part and gives you what you need.
Accuracy when converting from a Scanned PDF will depend on the quality of the source printout and the quality of the scan.