I tried many different channel managers before deciding iGMS was by far the best solution. It offers a ton of functionality that makes it easy to run a short term rental across Airbnb, Vrbo, and direct bookings - like a unified inbox w/ multiple users, automated guest messaging, cleaner management, and syncing with PriceLabs. While they have an ok mobile app (works on the go), the experience is very good on desktop. As a bonus, I'm also about to create a direct booking website using their WordPress widget, which integrates reservations directly into their platform.

Multi-calendar management and combined inbox features are the most critical and appreciated.

This software allows you to combine all your rental platforms into one system, saving you time and headaches of running a rental property