I've flown QR F a few times between LHR-DOH-HKG and QR J to CPT a couple of times.
I have been very happy with the hard and soft premium product, and would not hesitate to use them again. The ground handling and the Premium terminal at DOH are excellent as well. Sme other carriers could learn a thing or three from QR, especially when it comes to ground handling of premium pax at the hub.