I agree with lightyear40 . Both airlines have their pros and cons; I generally prefer EK, though an exception is if you get the QR 777 in C, which is an outstanding experience -- and they run the 777 to both BKK and JFK.

I have been lucky to never have significant delays with either airline, except for EK's morning flights to DOH, which I take all the time and which are very often half an hour late (I was an hour late last week).

Even though the transit in EK entails long walks, I prefer it over QR. I just don't see what's so great about the premium terminal -- I prefer the EK lounges, service, and, if I have any length of time to kill in transit, the DXB airport overall.