And for non-developers the screenshot-driven Kantu Web Automation Browser (Chromium-based, https://kantu.io ) is much easier to use than any tool that relies on Xpath and CSS Selectors.
I have not used iMacros before but did a quick check. I guess one of the difference would be it costs between $500-$3000 for different types of licenses (common for RPA software like Automation Anywhere or UiPath), while TA.Gui is under MIT license free to use/modify/share.
iMacros supports scripting by writing code, while one of the primary aims of TA.Gui is to minimize writing code while still supporting datatables, object repositories, incoming and outgoing API calls etc. I can't add more since I have not used iMacro but have noted this tool for reference.
For Kantu, it reminds me of SikuliX project, except that SikuliX is for entire desktop while Kantu is for browser. Have noted this down as well for reference :)
And for non-developers the screenshot-driven Kantu Web Automation Browser (Chromium-based, https://kantu.io ) is much easier to use than any tool that relies on Xpath and CSS Selectors.