I use the Axis Vistara Infinite.
Short answer: Worth it only if you travel frequently , and are comfortable sticking to a single carrier. If not, get a LTF diners black if possible.
Long answer:
10k annual fee
1 free business class domestic flight, 2 upgrade vouchers, club vistara Gold(Great perk)
10k points in first year(8k points for long sectors like delhi to blr)
I travel once a month, so vistara points accumulate. Also rewarded flights are good for emergency or flights during festivals when surge is higher. Got a business class flight day before Diwali when minimum cost was 12k
First year ROI is there, currently flights cost 5k min, so for 10k I get 2 good flights, 1 of which is business class so no pressure to spend.
Every 2.5L spends you get another business class ticket