There were over 90 changes to the facelift CT - a stiffer body by using more weld points and adhesives, revised suspension, revised steering, remapping of the engine/transmission to reduce noise under moderate acceleration, improved mpg, reduced CO2, styling and aerodynamic changes, improved interior trim details, improved infotainment system, new steering wheel etc.
I've not spend much time with either revision so not sure how much of a change you will notice day to day, most of the revisions are quite minor but all combined add up to a notable difference.