Aoa brother. I have bought cultus AGS recently on 7th sep 18. Regarding your query, gear shifting of AGS is so smooth that there is no jerk at all.
Before buying, there were many reviews on pakwheels saying k AGS bohat zayada jerk leti hai, lakin aisa kuch b nai.
If u slightly lift ur foot, the car changes gears so smoothly that it is not felt, the only indication on the screen shows that gear has been shifted. And even if you dont lift your foot from accelerator, even then gear changing is not noticable.
Suspension is no doubt really soft and ground clearance is as much as it should be for our Pakistani roads, no hitting on speed breakers.
I have shifted from passo hanna to this cultus and enjoying it.
I would prefer that instead of buying used vitz in the budget of 16k for 2015 model having mileage of 50K + kms, go for zero meter cultus with 3yrs warranty or 60,000 km. I have also purchased the 4th year warranty/80,000 kms for additional peace of mind.
So my vote is for cultus AGS. Please feel free to ask anything.
One more thing, AGS is not readily available aur jis dealership pe bhi agar available hue, they will ask for around 80,000 own/premium. So be ready for that if car is urgently required otherwise minimum 03 months waiting.