Ive made the flight several times, in both classes. YOu can expect NO PTV's, in economy, which isn't really that big of a deal. There is lots of TV's anyway, so there always visible. DOn't try and compare this flight to the DC-10. Not even close
Seating is always 3-4-3 on all NWA 747's. Seat pitch is pretty generous, and i think its a 38inch recline, which is better than most carriers so its pretty nice. YOu should get a small snack and a drink a little while into the flight before dinner. Ecelent award winning wine. Lol, they even gave it to me a minor! Food should be pretty good in economy, probably chicken or pasta, salad, rolls, dessert and maybe cheese and crackers. Portions are pretty good. THe bring around drinks (water and OJ) a few times during the flight as well as snacks, but not as much as KLM. Probably get yougurt, banana and a roll for breakfast. Try to get a seat near a emergency exit or a door, thatway you get several feet of leg room!
Personally, the service is just as good as AA, DL, CO and certianly better than UA. I think youd be satified, but some people are a little to picky and expect to much. If you had a chance to get a KLM flight though, TAKE IT.