I think I know what cle mean by the "different demographic" remark, in that it seems to be used more for local journeys than daily commuters. Lots of school kids, people travelling to stations, shoppers, local work places, etc. Although of course some commuters do use it, it's not for me - journey time (for my journey) is much faster by train/tube, and I don't like the unpredictable nature of bus journeys.