Recently, I had to use a Delta MCO for a flight from DEN-SLC. The fare on the day I purchased it was roughly $300 roundtrip. The next day, I happened to be on a computer at school that had sidestep installed, and decided to check it out. I found out the fare had dropped, and was able to call Delta, and get another MCO issued for the fare difference. I realize I could have done this on other travel software, and even the delta web site, but because it was there, and easy to use, it allowed me to save some money. I have not had any of the problems using expedia since installing sidestep on my home pc.