Well, the KMB's headrests are actually neckrests! It can't even
rest a 160cm+ person's head! Instead, they make you sit upright and
is pushing against your neck.
Of course the Citybus Trident coach ones are of a different story,
much more comfortable.
At least in Singapore you all don't really choose for a AC or
non-AC purposely due to the fares, but in HK, it really matters if
it's an AC or non-AC. A non AC buses costs HK$10 while the AC can
cost $14! But this is for KMB only as NWFB and Citybus are fully AC
now.
Leonard