Screencastify is a suite of video-creation tools for the classroom, from the company of the same name Chicago. It is used in K-12 classrooms around the world, for teachers and students, to create instructional videos, record presentations, and give better feedback, and to support remote learning.
Screencastify is great for beginning video creators or teachers who need a tool to quickly record a screen. For those with a budget, the paid features offers basic editing and the ability to embed questions, which can make for a more polished and meaningful video. Screencastify is not for users who want to create a more polished video with an introduction or other media that needs to be included, such as background music or other images. My go to - if it's quick and easy, use Screencastify. If I want to make in-depth edits, use another solution.
Loom and Screencastify are the most direct comparison. They both are Chrome extensions that have a low learning curve for beginner users. Loom offers a pro license free to educators, which allows for unlimited numbers of recordings and a 45-minute cap on recording length, perfect for lessons. Screencastify's pro features are paid for but are also more in-depth. Their editing is more robust, allowing users to trim in the middle, not just the edges. Users also get unlimited recordings and no cap on video length, and some storage depending on the tier purchased. Screencastify also offers volume discounts, which can help reduce the cost significantly. Educators can also create assignments in Screencastify, which is unique to this product. Camtasia is a full-fledged editor and screen recorder, so a full comparison isn't fair, since the products have two different intended uses. Camtasia offers robust features to make a polished final video