I like how it integrates with QB so easy to see what's going in my schedule, also can view invoices from within app! The customer support was terrible when we were using an older version of their product years ago - they did not respond well at all if you had issues or problems with anything they offered; basically nothing but bad attitude/bad work ethic by employees there.
We used them because our previous scheduler didn't offer many features (such as task reminders). This one does everything your regular office-based schedulers do plus more!! It makes managing projects much easier than trying to keep track of tasks manually via Excel spreadsheets.