Hi Vishal:
I am glad that you had a pleasant TD experience with Honda Jazz.
Jazz and i20, both are luxury H/B with excellent built quality, reliability and emphasis to safety. Both have 5 Star safety rating but in terms of exact #, i20 has an edge. Both cars have similar dimension and features, except Asta has some more. Following data may help to choose b/w Jazz Base and i20 Asta (1.2L) (I kept 1.4L i20 out because it is little too powerful for Jazz):
Acceleration (0-100) 17.66 sec (Jazz), 13.36 sec (i20)
Quarter Mile 20.58 sec (Jazz), 19 sec (i20)
Braking (80-0)30.43 m (Jazz), 26.86 m (i20)
Braking (100-0) 48.09 m (Jazz), 43.02 m (i20)
FE (city) 11 kmpl (Jazz), 13.8 kmpl (i20)
FE (highway) 17 kmpl (Jazz), 18.5 kmpl (i20)
Safety Rating (NCAP) 5 star (Jazz), 5 star (i20)
Price (Ex-showroom, Delhi) Rs. 698,000 (Jazz), Rs. 560,201 (i20)
NOTE - Jazz @power # is 10% higher but it lacks low end torque, so it requires lot revving the engine and feels slower w.r.t. i20 (1.2L). IMO, 1.4L premium for Honda Brand is little too high.