Really Simple CAPTCHA vs. Stackable
Take a look at this side-by-side comparison of Really Simple CAPTCHA and Stackable.
At a Glance
Really Simple CAPTCHA
About Really Simple CAPTCHA
Really Simple CAPTCHA does not work alone and is intended to work with other plugins. It is originally created for Contact Form 7, however, you can use it with your own plugin.
Stackable
About Stackable
Stackable is a plugin for WordPress that offers a collection of blocks, templates, and other design tools to help users create custom, professional-looking websites.