I have never used a TA either. But for something this important as well as the coordination factor I wouldn't have booked any other way. TA's do this as their job, they have inside info that we do not have and they have probably seen every bad news travel story and know how to resolve them. I felt 100% comfortable using one. Plus they can get better rates for sure! And it allows you to focus on all the planning things you need to do, not coordinating all your guests travel and listening to their complaints.
For flights though, I find sometimes the reason they are cheaper is because they have weird connections and they are at really odd times. But if that doesn't bother you then that savings is incredible!