Which is the best option and less time consuming job for doing testing through MTF or with Selenium tool? and how?
Both the approaches have its own pros and cons. With MTF, you will have the readily approx 300 written tests are available and can be executed in any system. You have to write the scripts for your custom code changes of the site only. Execution time is more.
With Selenium, you have to set up and write the automation scripts based on the business scenarios.
Based on your project schedule/resources, you can choose the option.