I've been using ScheduleOnce to land meetings with my partners and employees for about 6 months now. I'm a web developer and in my spare time I run an e-coaching company based in Costa Rica, and getting everyone to agree on a time to meet was a constant challenge for us, since we all have other jobs to tend to.
We used to have to email each other back and forth, sharing our availability for the following week, and things would always get messy because we would miss an email or the process took so long that some of the spots weren't available anymore. ScheduleOnce got rid of that problem.
I can easily share my Google Calendar for the following week(s) and have my team mark all their free spots. Then we can easily arrange a meeting and everyone's response is kept in one place, instead of a bunch of emails spread across several days. Sometimes we even set 2 or 3 meetings at once because it's just so easy and quick to get everyone to commit.
There's one final advantage that might not be perfectly obvious... For some reason people tend to ignore emails regarding meeting times, or they procrastinate sending their calendars. But when we started using ScheduleOnce, everyone started feeling like they had to respond quickly because everyone's waiting for their availability to show up in the meeting page. They feel responsible, so our meetings get scheduled much more quickly. I rarely have to wait a day for everyone to respond and we usually have 5-8 people in our meetings.
I couldn't go back to the old ways now. ScheduleOnce just makes things easier.