Pros of Manual
•If the test case only runs twice a coding milestone, it most likely should be a manual test. Less cost than automating it.
•It allows the tester to perform more ad-hoc (random testing). In my experiences, more bugs are found via ad-hoc than via automation. And, the more time a tester spends playing with the feature, the greater the odds of finding real user bugs.
Cons of Manual
•Running tests manually can be very time consuming
•Each time there is a new build, the tester must rerun all required tests – which after a while would become very mundane and tiresome.
You can read a detailed article by Sara Ford from here
3 hours ago