1. REDCap vs Qualtrics - Similarities
GUI interface for survey-based data collection.
Branching logic
Anonymous Responses
Export to outside statistical software
Some ability to share and collaborate w/other users
View simple data visualization, graphs/charts
Pre-built forms to use as starting templates
Both platforms secure

2. REDCap Unique Features
Primarily for use as data input target for researchers themselves.
Multiple forms per subject, tracked by unique ID
Many sophisticated data entry and manipulation features
Calendar/Scheduling
CSV Data Import/Export
Record Locking
Data Comparison Tools
Data Quality Checks
API Access
Double Data Entry
Full logging of all actions taken in each project
File Repository for storage of study-related documents

3. Qualtrics Unique Features
"Panels”, a “focus group” of users for repeated polling with different
More built-in social media sharing functions.
Survey-building GUI is a little more robust, most notably having several question types not available in REDCap.
Accessibility checker verifies that responses can be entered with assistive technologies.

4. When should I use…
If you’re doing solely survey collection (user feedback on your website, course, etc), Qualtrics is your likely winner
If you’re doing any type of research (basic science, clinical, or otherwise), REDCap has many more research-focused features.