Bro I have this model bought in jan 2016 really satisfied but be careful with oil changes as @nabeel_ali said go for liqui moly 5w 30 for best fuel economy and smooth drive. Overall differences in this model and the old one (not facelift 2012) is that the new one has a fuel gauge analogue meter front is face lifted with smoked lights back lights and bumper are bit changed, reverse light is in middle instead of bottom like 2012 shape. Dashboard is black not semi beige like the 2012 shape and engine I don't know is changed or not but appearance is a bit different and I've heard that it's the updated edition of 1kr fe which has better fuel economy (not sure). Also the new model has a traction control switch and an active stability switch. Multi steering switches are really really common only few facelift vitz don't have them ( according to my knowledge)
And the fuel consumption part, my car with the original oil from Japan was giving 16.5 (with minor ac and light foot) to be very honest but as I changed the oil and used 5w 50 toyota taglon oil it dropped down to 13 14, i believe using liqui moly 5w 30 would give better results.
And my car has a simple key same as the Corolla Grande has excluding the trunk and siren switches. It doesn't has an immobiliser.
Good luck and overall I would say any vitz is the best 1.0 jdm regardless the model it's the best as i believe. :')
