Where can I get the customer feedback for this tour? What is the process of booking a ticket.

Sorry I don't find any reviews of the sightseeing tour. Maybe you can ask some from others on the Community column of this website.

There is always a ticket service counter that is located nearby the sightseeing bus. Or you can buy the ticket from the driver. Generally speaking, there are enough tickets. So it's not necessary for you to book it in advance. Have fun!