A year ago, we flew JAI-BOM on a JetKonnect 737-800 BSI, then BOM-CMB on a "mainline" Jet 737-800. Both J class flights were outstanding and I couldn't tell much difference between the two. Indeed, IMO they were as good as EY's regional J class. Some pics of each...
JAI-BOM JetKonnect Business Class
BOM-CMB Jet Airways Business Class