You go to the airline where you will upgrade the soonest(IMHO). And remember, you have to live the decision you make so keep in mind any and all advice. If I was at Jazeera I would want you to go to Gulf, you might be competition. If I was at Gulf I might or might not want you to go there(for different reasons). You need to make a list of priorities, an actual list(paper) and then review and compare the +/-.
Thats my two(2) cents of advice
