The TPMS on 1.5 is not manufactured by the same company as that on the 2.0 and 2.5 vehicles. The TPMS on 1.5 does seem to be highly reliable, whereas that on 2.0/2.5 appears not to be.
I also believe that the TPMS on 1.5 provides you with readings from the moment the car's ignition is switched...