What are the differences between CZ-Pdf2Txt/Simple/for Acrobat Reader/COM? 
Please see the comparison table

 Support Batch ConvertSupport Current ConvertSupport Acrobat Edit VersionSupport Acrobat ReaderSupport  command-line/ stand-aloneSupport COMSupport Sub-folder Convert
CZ-Pdf2Txt Simple
CZ-Pdf2Txt Simple for acrobat reader
CZ-Pdf2Txt
CZ-Pdf2Txt for acrobat reader
CZ-Pdf2Txt COM
CZ-Pdf2Txt COM for acrobat reader