Travel Pony has a lot of great deals on hotels, and often offers the lowest prices against some big name competitors. You can see some comparisons here.
Most reviews you come across about Expedia will include stories of people spending hours on the phone due to Expedia rescheduling trips, or confirmations not going through.
FareFirst is quickly growing to be the number one destination to compare and find the best deal for flights and hotels. The technology-driven approach finds numerous deals across the world and intelligently picks the best deals customized for you by filtering relevant deals. The service will always be free for everyone to use. FareFirst is not a direct booking service, It aggregate the results from various online sites and help customers choose from the best.