XL5, Crossunder is somewhat right: I personally have covered recently few new joiner F/Os with a major gulf carrier, guys with different backgrounds.
Jet experience did not seem to be an issue, BUT, airline experience appeared to be quite a big one, just like medium or heavy jet performance understanding and usage. Adherence to SOPs, scan and checklist discipline etc
Guys with T-Prop time and airline experience seemed to cut it better adapting faster to a new jet airliner than guys with whatever operator background and light, business jet or even heavy military jet experience !
I believe airlines should be looking for airline experienced pilots first, if they want to have decent operators fast !
Again, exceptions exist, just to confirm the rule, as the french would say.
Cheers