Always worth sending compliments rather than complaints, but I realise that a lot of what seems like kindness is actually just ordinary boring decent driving.
I've rung a few companies to make a mention. They are always surprised when it's positive.
ben/Yahuda: Yup, that's the route I use to register a complaint. It's not worth the hassle to try doing it by phone - you're bound to miss something. If it's a complex incident, I sometimes write a Word document to cut & paste so I know I've got it right before posting.
Useful information for reporting a bus: Route number, Registration, Time, Position, rough description of driver. Although I have been told that the yellow plate number on the side of some buses is important to identifying the driver, TfL don't seem to think so.
Useful information for reporting black cabs: Don't bother unless it's going to make you feel like you;'ve done something. The Public Carriage Office Will Not Act. Nor will the Met.
There may be a value in a sticky for how to report incidents. I know LFGSS have one on busses.
All that said, I spend an awful lot of time on bus-heavy roads, and have countless successful negotiations with them on every journey. Most bus drivers in London seem to be very competent and considerate.
