I have used the 381 several times a week for the last seven years until July this year. Where does one start?
It has usually been reliable in the mornings to Canada Water Station but about once every month it was dreadfully late for no known reason. In the daytime it always been frustrating as you can wait for ages then two or even three come along together. In the evenings it is silly that there is no indicator at Canada Water to tell you when the next bus was due, and its departure from there often seems to coincide with the less frequent C10 serving the Rotherhithe peninsular.
At other times, both weekdays and weekends I have travelled to Bermondsey and beyond, and these have probably been the more frustrating journeys. More than once I waited in vain for a 381 from Waterloo at various points along the route; when there have been roadworks the drivers seem to have been instructed to travel empty in order to make up time, leaving passengers at the bus stop! I ALWAYS got on the first bus heading east in order to get to Jamaica Road and have the extra chance of a C10 or 188 to get me nearer home more quickly.
There also a few cowboy drivers; once I actually caught (with one hand) an old lady who was falling as the driver braked VERY sharply for no good reason other than treating the bus like a sports car.
You won't be surprised that I am delighted to have retired and moved away. Yesterday we exchanged contracts so I won't be coming back!
Personally I also regard it as a very unreliable service and most drivers (with some noticeable exceptions) are not able or willing (?) to communicate anything, just treating us paying customers as a nuisance.
For example: deciding on a whim if they stop earlier than the announced stop or just being generally rude to tourists or people with questions / dissabilities / etc.
I try to avoid it with walking whenever I'm fit enough.