Just returned from a JFK-CDG roundtrip on AF's Affaires, and I can tell you it's a perfectly pleasant experience.
JFK Lounge: Food offerings were quite nice. Extensive crudites, roasted vegetables (including eggplant, asparagus, beets and other interesting things), some kind of couscous salad, a nice marinated salmon, poached shrimp. There are plates of cheese and decent bread. Self-serve bar, where champagne (Pommery) flowed. Shower was ok. Oddly, the CDG lounges have very limited food offerings compared to their counterparts at JFK, though they have nice champagnes, including Pol Roger and Duval-Leroy.
Flight: Service is quite nice, cabin is clean. Seats are angled lie flat, which I happen to find quite uncomfortable, and is the biggest drawback. Food is a quick one-tray affair for CDG-bound flights, to maximize sleeping time. When you're done with the appetizer (usually foie gras) they swap out for one of two main course choices. Wasn't great, but certainly could have been worse. The return is more elaborate, with a plated amuse-bouche, four main course options and separate cheese and dessert service
Seating: For me, AF's biggest problem is the angle of the seats, which varies depending on the version of the seat. All are "lie flat" but some are more horizontal than the others. (Also, the 340 has 2x2x2 seating, while the 772 has 2x3x2. It's possible that the seats on the 340 are a bit wider as a result, but I can't be sure.) In any case, I find the seats quite hard, and generally very uncomfortable. The slope of the seat is bad enough... but there's no flip-down "bottom" to the leg rest, so your feet just kind of dangle off the end and it makes it easier to slide down the seat. The other night I was exhausted, but still had trouble getting more than couple of hours of sleep. (I never have much trouble sleeping on the DL cradle-style BE seats.) AVOD is available on all flights, with a decent selection.
In all, you could do a lot worse than AF Affaires, though I also enjoy flying DL's BE product. I'd say it's a wash.