The worst that I took was SBS7371J 
7448 to me is the worst. No to mention the rear is vibrating like
madness, the Front desto holder's cover is even vibrating which
caused for the irritating sound made. Because of the rear
vibration, i sat at front. However it's worst. I rather have
vibrating seats than the noise.
So, every depots got bad and good buses. No need to argue which
depots is good or bad. Keep comments to yrself so that no one is
being "offended" though.
Asking BC for opinion is no much better to know about buses. For
eg. Some BC hate 9680D for slow acceleration. However, some BC love
the strong aircon, having opportunity cost of better acceleration.
There is even no room for discussion on which bus is good or bad
either, giving the different wants or even the expectation
from buses we have.