What is Appium’s most considerable limitation?

Hand down my chin starting thinking and mumbling. If I had to provide one single thing you should be aware of about Appium before starting using it, it would surely be multiple session handling. Since Appium is a server, it serves HTTP requests; you might have two different computers running a test each against the same Appium server: what happens? As for now, Appium does not support this scenario and the second test will be aborted.

This is a considerable limitation because no queuing system comes with Appium. If you need to support multiple sessions, you will need to implement this feature by yourself.