What are some alternatives?
When comparing KEL CHM Creator and Adobe RoboHelp, you can also consider the following products
Chmox - Chmox is a free (of charge), open source application for OS X which lets you read Windows Help...
MadCap Flare - Documentation for Any Audience, Language or Format
CHM Editor - Best solution to edit CHM files
HelpNDoc - What is HelpNDoc ? Easy to use yet powerful help authoring environment which can generate various documentation formats from a single source.
Dr.Explain - Dr.Explain software is a help file authoring tool.
Helpinator - WYSIWYG, single source, multiformat, multilingual help authoring tool with screenshot capture and annotation. CHM, PDF, WebHelp, QtHelp, JavaHelp, OracleHelp, WordPress. 249USD.