This is app is VERY limited in functionality, especially considering price. Note that for Shopify Plus users, this app offers only one price point: $99/month!
Showstoppers for us (other than price)... It has no backend calendar to view bookings, no way to edit/view/delete bookings, not even a notification email for bookings (that I can find). The "Manage rental schedules" feature advertised on the app page is very misleading. So the management side of the rental process is wholly missing.
There is also no support for variants (e.g. a rental product with multiple sizes/colors/types).
What did work well was the simplicity of blackout dates and rental policies. It was easy to select weekends as blackout dates, for example, so that rentals could be not started or returned on a weekend.