When2Meet is described as 'When2meet helps you find the best time for a group to get together. It is a free survey tool that is quick and easy to use' and is a appointment scheduler in the business & commerce category. There are more than 10 alternatives to When2Meet, not only websites but also apps for a variety of platforms, including SaaS, Android, iPhone and Self-Hosted apps. The best When2Meet alternative is Framadate, which is both free and Open Source. Other great sites and apps similar to When2Meet are Doodle, Crab Fit, zcal and Calday.
While both When2Meet and Framadate serve for appointment scheduling, their time selection interfaces are quite different. I would say that When2Meet is more intuitive for uninterrupted time blocks (even like the same time during several days), while Framadate works better when time is more discrete. Framadate beats When2Meet as a free and open source software.