Which J service to chose? DL, EK, CX, or AF?
I actually think DL's long haul J product is perfectly fine, and completely adequate if their schedule & pricing is equal or better. CX, EK, and SQ will be better J products, but I wouldn't really pay a huge premium for them, nor would I go out of my way route/schedule-wise just for the product. And if you're building miles/status with SkyTeam, there is value in that as this sounds like a trip that will generate lots of miles.
The only J product I might avoid is AF on certain equipment. But again, if you can get one of their new 777s or if their route and schedule is significantly better, it is still a perfectly fine way to get from A to B.