Qatar Airways is fine until something goes wrong. Then, if you are not Caucasian or Arab, you are toast.
A few years ago, flying QR on a paid Business Class ticket, our original aircraft went tech and they subbed a 2-class plane for a 3-class plane and had to downgrade F->J and J->Y. Instead of downgrading the passengers who had been op-upped from Y->J, they chose to do to the downgrade by ethnicity.
I was paged in the Premium Terminal and advised of the situation - my ticket (still a paper ticket back then) was stamped "INVOLUNTARY DOWNGRADE" and I was handed a new boarding pass for a bulkhead aisle seat in Economy Class. It was myself and 5 others downgraded - all of us either South Asian or Far Eastern, while a Caucasian gentleman who I had been talking to earlier at the Premium Terminal and who had been op-upped was left in Business Class.
I was then asked to collect my belongings and was escorted out of the Premium Terminal - the reasoning being that the Premium Terminal was only for Business Class pax and I had now been downgraded to Economy. I was then paged in the main terminal and my bulkhead aisle was swapped out again for a middle seat further back as the bulkhead was a bassinet and pax with infants had priority. When I asked about taking the next flight in Business Class instead, I was told that I would need to pay a fee to do this as my ticket did not permit a "stopover" in Doha.
Oh, did I mention throughtout this that I was also Elite with QR at the time?
After contacting customer service after the flight, I subsequently was given the offer of either the difference between half my discounted J-class fare and the full Y-fare (which worked out to <$100 as I had already flown the first leg in J-class), or a complimentary upgrade on a future flight on the same route. I chose the complimentary ugprade which I used a few months later without any problems. They also credited me a handful of miles (although I only received Y class miles for the route I was downgraded on).
I've switched to Emirates since then and while they have their faults and preference for some ethnicity of passengers, it is not as institutionalised and blatant as Qatar Airways is. So for those who are thinking about switching to QR, look in the mirror and if your skin colour doesn't match what they want to see, think again...