We did Kingfisher on BLR-DEL in early December. I guess we got lucky as the flight went off without a hitch. And overall I was impressed with the service. If they're still having operational problems, I guess it's not a good idea to book them though (they weren't when we originally booked back in October IIRC).

We also had a good experience on Indigo on another route. We didn't much care for JetLight (old plane, very tight legroom).

And be careful on the AA mileage earning - many of the cheaper fares don't earn anything. Check the chart on AA.com.