I've flown AF, KL and DL across the pond a few times in the last 2 years. They were all enjoyable, but as between AF and DL, I'd fly AF for the food and drink (AF better than DL slightly), and DL for the seats (AF's sliders are too uncomfortable unless you take a strong sleeping pill).
AF's headsets are not completely hardwired: you can pull out the plug and use your own headset.
One other benefit of flying AF is you are more likely to have an empty seat next to you because DL is, like many US carriers, extremely generous with NRSAs. I would take an AF flight with two seats for me to spread out over any single DL seat any day (though the reverse is also true).