I will be there in March.

I would suggest Korean, as their new business class is quite nice. Lie flat seats with AVOD. The new AF business class is supposed to be nice, but lie flat at an angle. KLM is still behind the times on the routes I have flown them. It has been a long time since I flew Lufthansa in business class so I cannot give a reasonable opnion there, but you will not get Skyteam miles credit on LH. I've never flown EK. Alitalia I avoid whenever possible.