Two different design in Drupal website My website has two designs and I not sure which one is better. I am thinking upload both of them.

Here is my question: Is drupal able to let 50% of the user see design A and the rest is able to view design B. After one month later, I am able to see a report which one is better.
The closest thing I know is:
Switchtheme

Adds a block to allow users to switch between enabled themes.
Themes can be given 'user friendly' names and access can be controlled
by user role.
Switchtheme provides optional support for Browscap module to switch
themes based on the browser of a visitor.