Don't bother with FlyDubai. The pay is decent, but you'll spend it all on housing and the cost of living in Dubai which is really high. They also fly quite a bit of backside of the clock (redeyes) and to some really bad places. Also, I will promise you this... you will have never been as tired in your life as you will be with either Emirates or FlyDubai.
Fatigue is a real concern there, but their GCAA (authority) attitude towards it is something that will leave you scratching your head and wonder if these people are in the same century as the rest of the world. For example, if you call in fatigued, their rules require the company to give you 48 hours off (good)... but then you have to go see your aviation doctor to root out why you were fatigued (really bad). In other words, you can't just say "these rosters are killing me" because the answer will be "... but it's legal 'captain'..."