No parts issue sir. parts are availalbe everywhere, there are almost 40,000 santros in Pakistan, and Hyundai is not operating here since 2009, so what you think from where the parts for 40,000 santros are coming?? you can even find chinese, Tiwan, local and Korean parts for Santro in different quality and price tags, atleast buy an EFI engine for better consumption of Petrol in case if you don't get CNG in future.
For Pick i think it is power to weight ratio, santro is heavior than other cars mentioned, but not that much noticable difference.
look for small local cars feature, like suspension, engine, transmision, small local cars safety, trunk space etc before buying anything.
http://www.dewan-motors.com/hyundai/santro_Club_pernsa.htm
http://www.dewan-motors.com/hyundai/santro_Club_spec.htm
http://www.dewan-motors.com/hyundai/santro_Club_interior.htm
http://www.dewan-motors.com/hyundai/santro_Club_exterior.htm
And the choice is yours, you may go for any car you like.