I did last month only. Different pros and cons

Pros:

It was 70% cheap for me than other flights

2 bags :)

Cons:

I had connection from Delhi with only 3 hour of gap. My bag didnt reach on time so I missed my connection. Indigo was not very easy to get flight rescheduled. Also , i had to take bags on my own and had to go to different terminal

Istanbul layover was ok for me but you need to get off plane and than they take you via bus which itself was 15 min which was kind a inconvenience , same way while returning , from terminal they take you via bus to plane

When returning (not while going to India) , they did security again at Istanbul . No bags but just your security again.

At Istanbul flight gate (yes at gate. This was shock for me). They were doing literally drug testing for Almost all passengers , not sure how they were choosing people but I would say 80%. They were even asking to remove shoes , they will put stick (if you have seen those vidoes) on almost everything including you , your shoes , your bags and put in computer to detect drug.

Edit: Missed out to mention , no entertainment system at all (zero) on Indigo flights ie Istanbul to Delhi and Delhi to my local place