Air India on the JFK-BOM/DEL seem very reliable, they have 77Ls and are the crown jewels in the Air India network as far as prestige is concerned.
The aircraft spend literally the whole day at the destination so any technical faults are usually dealt with in a timely manner.
Domestically i got no idea regarding Air India but some flightz are operated by Indian Airlines under an Air India flight number. The two airlines are in the process of/or just finished merging to form a united front against Kingfisher/Jet!.