We've used Expedia for family holiday package and then just for flights or hotels. Our experience with holiday packages is that there always seems to be details lacking, customer service doesn't seem to know what is going on when I have called a few times and the package isn't always as advertised.
Now booking just flights or hotels, I have never had a problem. Probably because these are the easiest bookings and I have never needed to call into customer service for this.