I can only speak for myself, but I didn't even try Emirates because I was only interested on DEC and Emirates and the other UAE airline were admiting only FO at that time.
That being said, the selection process at Emirates is longer and more compreensive, but I' ve done all of those tests/interviews when applying to my current airline and passed without any problem. So no issues there...
In my opinion, if you look to the expansion plans of QR and also Qatar as a country, your doubts will be cleared. QR is the best bet in terms of future, financial security and quality of living. My belief is that in 5 years both Qatar and QR are going to be better places to live and work than Dubai and EK.
But I may be wrong...
Other opinions are welcome...