Don't know about QR, and not sure if that route has EK lie flat seats (which it does on the US-DXB routes I normally fly), but here's a quick comparison...

Seat:
- CW is true flat, 2-4-2, has extra privacy because of the front/rear facing setup
- EK J is fake-flat, although very good with lots of pitch, 2-3-2 front facing with less privacy than CW
- Winner: CW for me

Entertainment:
- CW is alright I guess, I never really use the AVOD
- EK AVOD has a ridiculous amount of content. If you're in their newest J cabin with the lie-flat seat, the TV screen is massive (23 inches touchscreen). But the kicker is this: you get a mini wifi-PDA attached to your seat which wirelessly controls playlists and acts as a remote control. I usually have the airshow running on this while I have a movie on the "big screen"
- Winner: EK by a country mile

Food:
- CW is blah
- EK is a little less blah
- Winner: AA (seriously, I think AA has the best on board food offering... not that you asked)

Service:
- CW is usually pretty good but I've had a few FAs that didn't seem too interested
- EK tends to usually have incredibly courteous, really good service, although the standards can vary here too
- Winner: EK, but marginally

Lounges:
- BA: Galleries F, if you have access is incredible. Club isn't bad too
- EK: You won't get into the EK F lounge in DXB, but the J lounge is pretty good too
- Winner: BA if you can get T5F, EK if not

FFP:
- Full TPs with BAEC and actual miles flown + bonus
- The "new" Skywards sucks. Period.
- Winner: BA by light years, really