I installed and set up the extension in no time. Totally intuitive.
Mine is a multi-language site (Spanish / English) and the language switching works perfectly... except for two details:
(1) The Custom Message in Redirect tab is global, and I think it should be an option for the Menu Item, attached to the language, so a different "Thank you" page can appear depending on the language.
(2) The Captcha language selection should also be an option of the Menu Item, instead of global, so the right language help text appears when clicking on the Captcha help icon, depending on the language of the page.