For me, SBST as they organise their fleet of 2000+ buses better.
It is NOT true that SBST drivers drive slower, there are plenty of
examples out there.
TIBS give the impression of being direct is because of the
geographical location of the towns they control. Bt Batok and CCK
are basically land locked areas. Woodlands is accessible easily as
there are a lot of empty non residential developments surrounding
it. The real problem comes for Sembawang, it has to pass thru
either Yishun or Woodlands.
However, for SBST, the towns that they control lie mainly on the
MRT lines. This means that the fastest way to go to city is to
bypass all the towns in the process, and as it is a residential
area, the there are more traffic lights and pax and school zones.
Hence, it gives the impression that SBST is slow and winding.
Its a pity that CSS is going off soon.....the buses are very
nostalgic, and wads more, the fares are very cheap and non rip-off
at all. 
