On a trip last winter around India, we flew Jet, Indian Airways and Sahara and found Sahara to be by far the worst. Our Delhi-Goa flight was delayed for an entire day (every hour it was "just another hour"), we had to be re-routed, and our luggage took two days to arrive. When we got to Goa at 11pm instead of 10am, there were very apologetic people standing around who promptly gave us some money to replace our stuff. But two people who hadn't secured hotel accomodations in advance were pretty much SOL because by then everything was closed. Maybe this was an anomoly and they're really a great airline, but we wouldn't fly them again if you paid us to.
Safety-wise I would say they're fine.
Fwiw, I think it's funny that people are impressed that they're the third best domestic airline, when others have mentioned that India only has four domestic airlines. Not sure I'd boast about being number 3 of 4.