I am based out of India. But all my customers are in US, Europe, Australia, etc. When they open my calendar to schedule a meeting, they should be able to see my availability in their timezone and not mine. Also the email that they receive upon booking an appointment should be in their timezone, not mine. I am currently using appointlet.com which is pretty good. It also allows me to embed an intake form (with a few questions), an a payment for the appointment too in the same flow.