Drupal Rooms is a basic booking and room management solution for hotels, vacation rentals and B&Bs.
All future regarding booking solutions is concentrated on the BAT module - the Booking and Availability Management Toolkit that will offer both a D7 and D8 version.
For vacation rentals, hotels and B&Bs please checkout Roomify for Accommodations - a complete Drupal distribution based on BAT with integrated channel management.
Other Types of Bookings?
Rooms is quite specific to the accommodation use case, which it tackles end-to-end (from availability and pricing management to bookings and checkout). If you are looking for a more generic booking framework we developed BAT - the Booking and Availability Management Tools for this purpose. BAT handles any type of bookable thing and any time granularity.