From 3.8 onward Appointments calendar will load instantly, regardless of how many appointments are active. Calendar will use lazy load to render appointments and also cache the output so everything is zippy fast.
Calendar Lazy Load
Appointments and calendar’s availability will be loaded after the page has stopped rendering, so customer doesn’t wait when you have large number of appointments or availability rules present.
Dashboard Widget
Staff can see new (monthly) appointments and appointments pending confirmations in a dashboard widget.
At first glance it looks perfect AND simple. I’m working on a yoga class schedule in WooCommerce and so far this looks like it can do more than anything I’ve found so far.