Flying Saucepan - the 737-400 FNPT II at Oxford is as realistic as they get; full visuals, full motion (yes, like the airline sims), and you do get to do some jet handling as well. The only thing it won't do (because of computer limits I suppose) is VNAV; but you get around it by using V/S or LVL CHG instead. I used it for MCC in Jan and really loved it (I wasn't a big fan of sims before, having only sampled a fixed-based Beech200 FNPT II for the IR). I spent ages on 737-500s flight decks when cabin crew last century, and the 737-400 sim looks exactly the same. By saying it's generic, they mean it's not "taylor-made" to any airline's specific requirements in particular as far as flight deck details are concerned.
I also researched Jetlinx at the time, but while the 757-200 sim at Cranebank looks great (it's one of BA's own), they are about £700 more expensive and only do one MCC course/month. Jetlinx, however, comes highly recommended.
Cheers