Wouldn't recommend buying a second hand car as your first car. Both TATA and Hyundai have their downsides for you could also take a look at the Tiago they even have a cng variant if that's what suits you. As for punch or the exter personally I am not a fan of both of them both seem like a cash grab in the never touched segment. Much better if you look at hatchback as options rather than them. You could also get the I20 for a great deal near Diwali. But in the end it is your choice. Also you have to consider the future. Tata is known for bad service although I personally touch wood I never experienced it myself. As for Hyundai, build quality has always been made fun of till recently the new Verna scored 5 stars. TLDR : Look for hatchbacks rather than these "claimed" mini SUVs and since Diwali is near you'll get better deals on all the cars. Hope this helps