Last time I checked with Jet Airways was in 2008, so a long time ago, and maybe their policy has changed meanwhile (although doubtful that for the better).
No chance for an expat for any kind of progress, i.e. upgrading or fleet transfer. You join on one type for a certain position, and that's where you are going to stay for the duration of your contract.
Jet Airways only offered a contract limited for two years. As I said, that was 2008, maybe it's different now.
Salary offer was quite good, roughly the same what they pay at Emirates. I had applied for the 777, for which the situation was quite different than for the 737:
- live at home anywhere in Europe; you'll get a ticket from your nearest international airport to either LHR or BRU with a major carrier.
- duty starts at LHR/BRU, fly for 20 days (e.g. LHR-YYZ-BRU-BOM-LHR-YYZ-BRU), hotel accomodation is provided during your lay-over
- duty ends in LHR/BRU, where you get a ticket back home, then ten days off.
You should write them an email and find out what the situation is like now.
However, I believe it's unlikely that they'll put you on long haul ops without a rating and experience on type.