ERN3143, welcome to the forum!
Being a one sheep burner and being god or bad at copying movies is completely unrelated!
The no sheep ... three sheep burner, classification is for when you want to copy some (older) games on CD media.
Whatever number of sheep a burner has, it makes no quality difference when burning CD media with something that isn't copy-proteced, and it has no impact on DVD burning either.
I think the NEC ND-3500 is a very good drive, also for burning movies, but in my opinion it is not a very good 16x burner, so I suggest you burn movies at no more than 12x on the 3500.