I flew the Q suites on 777 (BLR-DOH) and A350 (DOH-JFK) and I much much preferred the 777 over the A350. More comfort, more space, and the washrooms are more spacious.
Also, the DOH-JFK leg was 14 hrs non stop, and Qatar did not provide any mattress, so it was quite uncomfortable to sleep for such a long time. Since BA and Emirates do provide a mattress, I will choose them anytime over Qatar for such a long flight.
Food wise and service wise, the Qatar flight DOH-JFK was quite a disaster. Maybe their staff need to undergo some training at BA or Emirates. They served the drinks nearly an hour after take off, then the entree after another hour then the main course after another hour!