Which one do you prefer?
I think both are as good.
SBST Citaros have powerful A/C and nice interior designs while SMRT Citaros have varieties, ZF, Voith and demo 136C.
Neither are drivable for the driver without being constantly kicked down... so no preference... although it seems that SBST's Citaros generally have noisier aircon but they auto-kickdown on 2nd gear onwards.
Powerful aircon?