I agree with the overall sentiment here (NickB, Johan Rebel), that the product is mediocre, yet stable. Sometimes it is hit-or-miss regarding the crew (either very attentive, or more self-interested in the galley), but in general, the product is OK. I'm definitely not the one to turn a blind eye to the monopolized AMS-NWI connection and the lacklustre service there, as KLM proves they CAN do it on similar connections, yet refuse to do so, due to "no competition".
Besides, as stated above, the Y product gets more meager by the year, excluding all kinds of things (free bags, lounge access, free seat selection) that used to be there in the past, while ticketprices have actually gone up.

The meals on KLM have been decent at least, especially with the new meal boxes in the Embraers. Tasty and good, even though the meal is served cold.
AF is more hit and miss, their meals are good in the planes with an oven, but their Embraers are horrible. Either some undefinable cod or beef with past-date vegetables. The champagne on board is a big plus though compared to the cava on KL.
All in all, I think KLM has a better product with their CityHopper compared to AF's HOP, however when the 737's and A319/320/321 (the A318 is a horrible plane with those slimline seats) come into play, AF wins the battle.