I always book with expedia and I probably still will in the future. I only booked with brand name hotels and have had great experiences, but my last trip I decided to try something else and it was an awful experience.
The 5 star hotel with good reviews on their site was so terrible (noise, bugs, mold, etc) we left in the evening and stayed somewhere else! After calling expedia 5 times we got a voucher for the price of the stay at the hotel. To be fair, I think all of this was mainly the hotel's fault, but the expedia employees kept on promising to look into the issue and get back to us the next day, which never happened.