this is pretty cool and it will definitely get you strong and looking good, when I'm hanging out with friends in NY we do pull ups on the metal over passes for kicks.
Its fun, creative and far superior to any gym, but your body weight and high reps will only take your physique so far before you will need a gym to put on greater size. I don't see many people on this program breaking 150 -160 lbs.
For anyone getting into fitness this type of unconventional training is the best place to start, stick with it for awhile and then join a gym to take your results to the next level.