2 nine hour flights. First on a delta 767. Second one Klm a333? I've never flown on either?

Mission trip to Uganda. The first leg is Atlanta to Amsterdam on a Boeing 767. The second from Amsterdam to Uganda is on a Klm Airbus a333. Since it is a mission trip, we ride in coach. I've only flown internationally a few times and they were all Business class on a 747. When I fly domestically, it's Business class usually on a 737 or 727. So basically, I was just wondering what to expect on both aircraft. Which one is better? Also, how does KLM compair to Delta? I've never flown KLM before.