Given the early life stage of TidyCal, it's already a solid challenger to Calendly's free level. It looks a lot nicer as an embed, and gives the basic functionality you'd expect.

There are a couple of things that it needs to make it more than bare bones, though:
- It absolutely needs proper Zoom integration to generate a link for each meeting. Currently, I need to send the meeting password separately, and overrunning meetings can only be managed via the waiting room.
- The logic for suggesting meeting times seems a bit basic. If I am free from 1pm-4pm, TidyCal suggests 1pm, 2pm, 3pm as start times for a 50 minute meeting, whereas Calendly suggests 1pm, 1:30, 2pm, 2:30, 3pm. Obviously this is more flexible for clients
- Defining the 'from' address for invites to come from. My gmail calendar is my main calendar but not my main business email address, and I'd rather clients didn't have that address.