It's ease of use, reminders and calendar integration.

i like how easily you can book a time and see the different availabilities togather

I use Roomzilla daily, and it's a huge convenience. It's super easy to make a reservation, because the interface is fast to use and has an intuitive timeline booking system. Usually I find and reserve a meeting room in just a few seconds, which is awesome. Advanced filtering options make it easy to quickly check which rooms are available and whether they have the necessary equipment. I also really like the maps included in the interface, I always struggle with the fastest path to the available rooms, so it helps me not get lost. For over a year of using Roomzilla I haven't had a need to use customer support, so I find it reliable.