Cal.com has been amazing for me. I just love the UI and UX and how seamlessly everything works in cal. I have forgot the overpriced calendly I was using earlier.
It's pretty easy to setup and offers a ton of nice features. I embed it on my website and have link to my profile in my email footer. Works very well, can't wait to use it even more in the upcoming months.
Had an issue logging in and Peer (CEO) tended to the matter within the hour. I haven't had such responsive customer service so this was quite the experience. It's refreshing to find a customer-centric open source project do so well.