Hands down the best, or rather the least painful, experience I have ever had booking a flight online. EVAR
Before this I used to loathe booking flights. It used to be a multi hour, tedious and toilsome affair trying to get the right combo of a good price at a decent time with enough wiggle room between flights. Especially if you are flexible with dates and cities. Some towns are expensive to fly in and out of. It can add $100-$200 to the price easy. I mean, screw getting up at 3-4am to catch a 6am flight and/or running to catch a flight or missing it entirely because of a delay.
Mad props to the Google code poets! One thing I have learned over the years is that the easier a complex app is to use, the harder it was to make.
Super easy + super complex = Hard as hell.