TIBS/SMRT my preferred operator over SBST !
But my selection is largely based on the bodywork issue of their
buses only as i personally don't find overall too much significant
differences in their service quality which i consider as relevant
to me.
Therefore because i take the other factors largely as 'constant',
the single most obvious difference is the superior class of (most)
of the bus bodies used in TIBS/SMRT fleet.
I consider the Hispano bodies overall definitely superior to the
Alexander, Duple-Metsec & Volgren bodies is soildness of
construction, finishing & trim quality even aesthetics. But
most importantly to me the Hispano bodies does NOT tend to emit all
those annoying squeaks, rattlling & cracking noises so
notoriously famous in the British & Australian bodies which
unfortunately consitute the SBST fleet while TIBS/SMRT only have
some.
On the majority of TIBS/SMRT fleet, any squeaking, rattling noises
tend to originate from loose (non originally standard) fittings but
not from the bodywork itself & the probability of getting a bus
which does NOT squeak, crackle or rattle is very much HIGHER than
on TIBS/SMRT & almost zero on SBST buses !
For me, that alone is excellent reason to board a TIBS/SMRT bus
over another from SBST @ a bus-stop if say both going to the same
destination i want to go to & same route or time ! Even if that
costs a higher fare, i'll still select the same !! I don't mind
paying any premium fare for such superior bodywork !
Resolution of any bodywork noise irritants on TIBS/SMRT buses are
more obvious & straightforward as such, compared to the
situation on SBST vehicles whereby the standard of those bodywork
are 'like that' only so what to expect ?!
So overall (for me) because i tend to get (otherwise similar) bus
with superior class of body from TIBS/SMRT, i select them over SBST
! In cases when i meet up with a TIBS/SMRT bus using the other
bodies, then my preference for TIBS/SMRT over SBST becomes almost
nil, instantaneously. Both then roughly equal in appeal to
me.