Having flown BAH-LHR via DXB outbound (Emirates) and DOH inbound this year - most recently on QR recently this week in J I was going to post a similar thread asking why on earth I should stick with BA.
Both QR and Emirates are not perfect, but when I look at the experience I had on my daytime flight, with a superb lunch, attentive service, comfortable seat and good amenity kit etc, plus access to the 1st class lounge in Doha (on QR their local J is marketed as F and permits access), for less than half the price of a BA direct flight and only about 4 hours longer travel, its a complete no brainer.
I want to love BA, but the more I see of QR and Emirates and what a good experience should be like, the less inclined I feel to fly BA. I'm on the BAH-LHR next week with BA, which anecdotally has been a lot quieter than usual since the ending of the DOH shuttle, particularly as its got tough competition from Gulf Air and feeder flights (at the bottom end of the market you can with reasonable notice get flights with Turkish for £125 from BAH to LHR). I'm not expecting anything great, and as I'm flying VS PE to NYC at the back end of next week, I almost expect to see a better service there than on the CW sleeper.