I've tried a bunch; I usually end up doing a copy/paste using a
   different PDF reader like Foxit or .. oh that old one that's
   shareware ugh - into Word and then going through some quick
   reformatting.
   I've got a buttload of windows PDF --> xxxx converters; they all
   work to varying degrees.

   Try [1]https://www.pdflabs.com/tools/pdftk-the-pdf-toolkit/ if
   you're comfortable with command line - it's free. I once
   converted a 1200 page thesaurus to text that way (don't ask why)
   - by using it to convert first to BMP and then I was able to
   sharpen them in bulk (using Irvanview or imagemagick - not sure
   now) - and then I used *something* to OCR them into text. (I
   don't remember what now)

   But I'm a textfile kind of guy; I usually bring things down to
   txt and *then* bring it back up into Word or whatever I need to
   use.

References

   Visible links
   1. https://www.pdflabs.com/tools/pdftk-the-pdf-toolkit/