We flew over on a 777 and returned on a 747. Both flights were comfortable. I wish that I had considered the airlines offer of an upgrade to business before I printed off the boarding passes so we could have gotten some sleep. The stewards were very good.

We flew KL1168 from Helsinki to Amsterdam for our other KLM flight (KL621) to Atlanta.
With the announcement of a flight delay from Helsinki, I asked for help at Amsterdam to get through the airport. We were about 40 minutes late departing but made up 14 minutes. As we deplaned the flight attendant said someone would be waiting for us.
No such luck! We stopped the first electric cart we saw, but it wasn’t for us and we “weren’t on the list.”
We kept moving, made it through Passport Control & just kept going. Our flight was boarding when we showed up!
So the flights individually were OK, but if you can’t get help when you need it, what’s the point of paying extra for B-Class?
Further, our luggage didn’t make our flight, so we had to wait 2 days for it to be delivered (10:30 pm!) Good thing Atlanta was our final stop.
Again, service on the flights was good. Food was just OK, not great. We got our goodies bag, but no little China row houses with liqueur.
Overall we were not impressed.

So we got to Gdansk airport and they had no record of our flight booking. They were very helpful, and it wasn't the fault of the staff at Gdansk. We had to pay extra from our credit card which was of course refused due to suspicious activity (!). The flight was late leaving and we had 30 minutes to rush from one terminal at Schipol to another. The moving walkways did not all work and there are security checks en route. We just made it to our next flight but only because we are relatively fit.. Never again. They give you food on KLM but it was the same on each flight, a strange not very nice sandwich.

Flew with this this company a few times. Took a flight from Switzerland to the Netherlands and then the Netherlands to Birmingham. With both flights, the staff were super efficient. The first flight was none descript except for the fact the only food option offered were ‘cheese’ sandwiches. The second was a ‘snack’ which was not too bad.
My main moan about the Netherlands is its airport, it’s like a maze! I’ve done two transfers there now and managed to get lost both times - perhaps they could paint a line on the floor so that already stressed passengers can simply follow the coloured line to the transfer area/lounge!

Flying from Luxembourg via Sciphol to Manchester both flights delayed, this type of service is expected from the budget airlines but not from a so called reputable airline.
I have approximately 10 flights a month this was and is my last with KLM,driving is quicker and more comfortable.