I think you will find that I terms of bottom line a Flydubai FO will take home around 42,000 per month
Emirates FO around 39,000
It's just the way the different benefits are split up.
On the whole I can't see why anyone from Emirates would not want to move across....
If you enjoy watching paint dry and have lots of fun apps on your iPad EK may well be the job for you.
Flydubai on the B738 with more than 1 sector to fly would be much more interesting in my view...