I have travelled in Vistara for many times and recently to Goa.
This is a great flight, they provide good facilities to their customers, ground staff of Vistara is really very co-operative.
They have an additional class of tickets called premium economy( with bit better facilities than economy class) , better space/leg
room than other flights.
Onboard staff is really well maintained and well behaved. The meal provided in flight is also very hygenic and of good quality. and they have good number of flights available for most of the popular destinations.
Experience of travelling with Vistara has always been good.