I haven't tried KLM Business Class, but I have tried their Economy class, quite a while back and I'm ready to say that they are among the best in the world.
I have tried L'Espace Affaires, though. The service is good, crew is attentive. Service gets done, but not with abundance. The seats are old, one of them would not recline - they didn't even cancel it, so I got that seat.
I agree with Marambio that some of the crews will not look happy to you if you speak to them in English, but they'll get their job done. Sometimes, they may treat you like a child.
All in all, Air France is good, catering is excellent - the crew is average (sometimes, my return trip for example - the first leg of the flight was EXCELLENT), the seats are not very good (777-200ER still get the old seats) but they get the job done.
But, I would take KLM anyday, as I have experienced them in cattle... err... sorry, Economy (Y) class.
Gastón - The MD11junkie
There is no such thing as Boeing vs Airbus as the queen of the skies has three engines, winglets and the sweetest nose!