Even though the customer service was bad, i think overall it was a good experience.. Just few things ... We are from NJ, and the best thing is - you can park in Union square station, and just hop on from there.
I have visited Washington so many times, and if we have to go around ourselves, it is a lot of walking.. With Big bus , it is a lil expensive, but i think its worth.. especially if you have to visit white house , lincoln memorial etc..
Just make sure YOU DONT BUY OR TAKE THIS ON A LONG WEEKEND OR WHEN IT IS CROWDED.. we took it once when crowded, and it was pathetic.. Buses didnt arrive for more than an hour, because of the overall crowd (like during cherry blossom festival etc).. On a regular weekend, Ill surely suggest taking a big bus.. NOT ON A LONG WEEKEND OR ANY OTHER WEEKEND when Washington DC is busy. :) Enjoy your ride .. Especially when you have elders of people who cant walk much.