Experimental design, " how chatbots can impact on a user’s experience", is better to use within subjects or between subjects?

I have to do an experimental design about "how chatbots can impact on a user’s experience when using public transport websites to book journeys". I am not really sure what type of experimental design to choose, would go for within-subjects or between subjects?

To make it more clear we have:

• Between subjects (or Independent measures)

  Different participants are used in each condition of the independent variables. Each condition is tested with different people

• Within subjects (or Repeated measures)

  Same participants take part in each condition of the independent variables. Each condition is tested with same people

Thanks!