Finishing school at 16:00, the 16:08 #78 used to be the bus I got back home every day pre-11th November changes - with the only exception being when the 16:00 #2A was rather late indeed or I got out 5 minutes early and effectively managed to catch it when it was running on-time... Now it's the 16:07 #2A - which I can gladly say has not departed late once since I started getting it from 11th Nov. onwards!

It was a lot worse then than it is now, but it's still not perfect. I'd say three out of five days a week at the very least, it leaves late. And by 'late', that's anything from 2 minutes late to 12 minutes late.
By the time it gets to The Wavendon public house on Chester Road (my stop), it has to battle the rush hour traffic - causing it to have an additional ten minutes lateness.

I've had some problems with the 78/78A on Sundays too, running up to 20 minutes late.