I own a Terrano for nearly 2 years now and a few reasons why I chose it over Duster:
Post-sale service quality is much better. This might be subjective but the service center that caters to my car is very good. I owned a Nissan Micra for 4 years before upgrading to Terrano.
Noise Insulation is better. Also, Nissan has added ~100kg to the Terrano by the way of few metal changes. It feels better planted and solid.
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Moseo
Tow truck owner